1178 lines
40 KiB
Zig
1178 lines
40 KiB
Zig
const std = @import("std");
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pub fn main() !void {
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const Enum = enum { foo, bar, baz };
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try execute(
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std.io.getStdOut().writer(),
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.{ .test_tmpl = "{.x} {%context_foo}" },
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@embedFile("./test.tmp.html"),
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.{
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.community = .{ .name = "abcd" },
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.foo = [_][]const u8{ "5", "4", "3", "2", "1" },
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.baz = [_][]const []const u8{
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&.{ "5", "4", "3", "2", "1" },
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&.{ "5", "4", "3", "2", "1" },
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},
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.bar = .{ .x = "x" },
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.qux = false,
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.quxx = true,
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.quxx2 = true,
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.maybe_foo = @as(?[]const u8, "foo"),
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.maybe_bar = @as(?[]const u8, null),
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.snap = Enum.bar,
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.crackle = union(Enum) {
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foo: []const u8,
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bar: []const u8,
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baz: []const u8,
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}{ .foo = "abcd" },
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.x = "y",
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},
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.{
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.context_foo = "foo",
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},
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);
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}
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pub fn execute(
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writer: anytype,
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comptime other_templates: anytype,
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comptime template: []const u8,
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args: anytype,
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context: anytype,
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) !void {
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@setEvalBranchQuota(@intCast(u32, template.len * 8));
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const tokens = comptime parseTemplateTokens(ControlTokenIter{ .text = template });
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const tmpl = comptime parseTemplate(tokens, 0, .root);
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try executeTemplate(writer, other_templates, tmpl.items, args, .{}, context);
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}
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fn executeTemplate(
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writer: anytype,
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comptime templates: anytype,
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comptime items: []const TemplateItem,
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args: anytype,
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captures: anytype,
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context: anytype,
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) !void {
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inline for (items) |it| {
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switch (it) {
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.text => |text| try writer.writeAll(text),
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.statement => |stmt| try executeStatement(writer, templates, stmt, args, captures, context),
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}
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}
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}
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fn executeStatement(
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writer: anytype,
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comptime templates: anytype,
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comptime stmt: Statement,
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args: anytype,
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captures: anytype,
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context: anytype,
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) !void {
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switch (stmt) {
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.expression => |expr| {
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const val = evaluateExpression(expr, args, captures, context);
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try print(writer, val);
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},
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.@"for" => |loop| {
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const iterable = evaluateExpression(loop.header.iterable, args, captures, context);
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const subtemplate = loop.subtemplate;
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//std.log.debug("{any}", .{subtemplate});
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for (iterable) |v| {
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try executeTemplate(
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writer,
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templates,
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subtemplate,
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args,
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addCapture(captures, loop.header.capture, v),
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context,
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);
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}
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},
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.@"if" => |if_stmt| {
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const condition = evaluateExpression(if_stmt.header.condition, args, captures, context);
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const subtemplate = if_stmt.subtemplate;
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var was_true: bool = false;
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if (if_stmt.header.capture) |capture| {
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if (condition) |val| {
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was_true = true;
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try executeTemplate(
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writer,
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templates,
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subtemplate,
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args,
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addCapture(captures, capture, val),
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context,
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);
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}
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} else {
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if (condition) {
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was_true = true;
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try executeTemplate(
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writer,
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templates,
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subtemplate,
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args,
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captures,
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context,
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);
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}
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}
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if (!was_true) {
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if (if_stmt.else_branch) |branch| switch (branch) {
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.@"else" => |subtmpl| try executeTemplate(writer, templates, subtmpl, args, captures, context),
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.elif => |elif| try executeStatement(writer, templates, .{ .@"if" = elif.* }, args, captures, context),
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};
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}
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},
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.@"switch" => |switch_stmt| {
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const expr = evaluateExpression(switch_stmt.expression, args, captures, context);
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var found = false;
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inline for (switch_stmt.cases) |case| {
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if (std.meta.isTag(expr, case.header.tag)) {
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found = true;
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if (case.header.capture) |capture| {
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try executeTemplate(
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writer,
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templates,
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case.subtemplate,
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args,
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addCapture(captures, capture, @field(expr, case.header.tag)),
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context,
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);
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} else {
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try executeTemplate(
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writer,
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templates,
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case.subtemplate,
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args,
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captures,
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context,
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);
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}
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}
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} else if (!found) if (switch_stmt.else_branch) |subtemplate| {
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try executeTemplate(
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writer,
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templates,
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subtemplate,
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args,
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captures,
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context,
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);
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};
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},
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.call_template => |call| {
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const new_template = @field(templates, call.template_name);
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try execute(
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writer,
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templates,
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new_template,
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evaluateExpression(call.args, args, captures, context),
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context,
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);
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},
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//else => @compileError("TODO"),
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}
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}
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fn print(writer: anytype, arg: anytype) !void {
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const T = @TypeOf(arg);
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if (comptime std.meta.trait.isZigString(T)) return writer.writeAll(arg);
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if (comptime std.meta.trait.isNumber(T)) return std.fmt.format(writer, "{}", .{arg});
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@compileLog(@TypeOf(arg));
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@compileError("TODO");
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}
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fn Deref(comptime T: type, comptime names: []const []const u8) type {
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if (names.len == 0) return T;
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// Compiler segfaults when I use std.meta to get this info so we search it manually
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const field = for (@typeInfo(T).Struct.fields) |f| {
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if (std.mem.eql(u8, f.name, names[0])) break f;
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} else @compileError("Unknown field " ++ names[0] ++ " in type " ++ @typeName(T));
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return Deref(field.field_type, names[1..]);
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}
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fn deref(arg: anytype, comptime names: []const []const u8) Deref(@TypeOf(arg), names) {
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if (names.len == 0) return arg;
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return deref(@field(arg, names[0]), names[1..]);
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}
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fn EvaluateExpression(
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comptime expression: Expression,
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comptime Args: type,
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comptime Captures: type,
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comptime Context: type,
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) type {
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return switch (expression) {
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.arg_deref => |names| Deref(Args, names),
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.capture_deref => |names| Deref(Captures, names),
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.context_deref => |names| Deref(Context, names),
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.equals => bool,
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.builtin => |call| switch (call.*) {
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.isTag => bool,
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},
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};
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}
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fn evaluateExpression(
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comptime expression: Expression,
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args: anytype,
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captures: anytype,
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context: anytype,
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) EvaluateExpression(expression, @TypeOf(args), @TypeOf(captures), @TypeOf(context)) {
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return switch (expression) {
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.arg_deref => |names| deref(args, names),
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.capture_deref => |names| deref(captures, names),
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.context_deref => |names| deref(context, names),
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.equals => |eql| {
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const lhs = evaluateExpression(eql.lhs, args, captures, context);
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const rhs = evaluateExpression(eql.rhs, args, captures, context);
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const T = @TypeOf(lhs, rhs);
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if (comptime std.meta.trait.isZigString(T)) {
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return std.mem.eql(u8, lhs, rhs);
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} else if (comptime std.meta.trait.isContainer(T) and @hasDecl(T, "eql")) {
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return T.eql(lhs, rhs);
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} else return lhs == rhs;
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},
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.builtin => |call| switch (call.*) {
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.isTag => |hdr| {
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const val = evaluateExpression(hdr.expression, args, captures, context);
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return std.meta.isTag(val, hdr.tag);
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},
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},
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};
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}
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fn AddCapture(comptime Root: type, comptime name: []const u8, comptime Val: type) type {
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if (std.mem.eql(u8, name, "_")) return Root;
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var fields = std.meta.fields(Root) ++ [_]std.builtin.Type.StructField{.{
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.name = name,
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.field_type = Val,
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.default_value = null,
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.is_comptime = false,
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.alignment = @alignOf(Val),
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}};
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return @Type(.{ .Struct = .{
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.layout = .Auto,
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.fields = fields,
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.decls = &.{},
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.is_tuple = false,
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} });
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}
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fn addCapture(root: anytype, comptime name: []const u8, val: anytype) AddCapture(@TypeOf(root), name, @TypeOf(val)) {
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if (comptime std.mem.eql(u8, name, "_")) return root;
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var result = std.mem.zeroInit(AddCapture(@TypeOf(root), name, @TypeOf(val)), root);
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@field(result, name) = val;
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return result;
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}
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const TemplateType = enum {
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root,
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for_block,
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if_block,
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if_else_block,
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switch_block,
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};
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const TemplateParseResult = struct {
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new_idx: usize,
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items: []const TemplateItem,
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closing_block: ?ControlBlock,
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};
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fn parseIfBlock(
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comptime header: IfHeader,
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comptime tokens: []const TemplateToken,
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comptime start: usize,
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) ParseResult(usize, If) {
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const subtemplate = parseTemplate(tokens, start, .if_block);
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switch (subtemplate.closing_block.?.block) {
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.end_if => return .{
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.new_iter = subtemplate.new_idx,
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.item = If{
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.header = header,
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.subtemplate = subtemplate.items,
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.else_branch = null,
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},
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},
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.@"else" => {
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const else_subtemplate = parseTemplate(tokens, subtemplate.new_idx + 1, .if_else_block);
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return .{
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.new_iter = else_subtemplate.new_idx,
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.item = If{
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.header = header,
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.subtemplate = subtemplate.items,
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.else_branch = .{ .@"else" = else_subtemplate.items },
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},
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};
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},
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.elif_header => |elif_header| {
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const else_if = parseIfBlock(elif_header, tokens, subtemplate.new_idx + 1);
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return .{
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.new_iter = else_if.new_iter,
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.item = If{
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.header = header,
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.subtemplate = subtemplate.items,
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.else_branch = .{ .elif = &else_if.item },
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},
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};
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},
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else => unreachable,
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}
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}
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fn parseTemplate(
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comptime tokens: []const TemplateToken,
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comptime start: usize,
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comptime template_type: TemplateType,
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) TemplateParseResult {
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comptime {
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@setEvalBranchQuota(tokens.len * 100);
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var i: usize = start;
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var current_text: []const u8 = "";
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var items: []const TemplateItem = &.{};
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const closing_block: ?ControlBlock = while (i < tokens.len) : (i += 1) {
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switch (tokens[i]) {
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.text => |text| current_text = current_text ++ text,
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.whitespace => |wsp| {
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if (i != tokens.len - 1 and tokens[i + 1] == .control_block) {
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if (tokens[i + 1].control_block.strip_before) continue;
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}
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if (i != 0 and tokens[i - 1] == .control_block) {
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if (tokens[i - 1].control_block.strip_after) continue;
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}
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current_text = current_text ++ wsp;
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},
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.control_block => |cb| {
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if (current_text.len != 0) {
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items = items ++ [_]TemplateItem{.{ .text = current_text }};
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current_text = "";
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}
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switch (cb.block) {
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.expression => |expr| items = items ++ [_]TemplateItem{.{ .statement = .{ .expression = expr } }},
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.if_header => |header| {
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const parsed = parseIfBlock(header, tokens, i + 1);
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i = parsed.new_iter;
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items = items ++ [_]TemplateItem{.{
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.statement = .{ .@"if" = parsed.item },
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}};
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},
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.for_header => |header| {
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const subtemplate = parseTemplate(tokens, i + 1, .for_block);
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items = items ++ [_]TemplateItem{.{
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.statement = .{
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.@"for" = .{
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.subtemplate = subtemplate.items,
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.header = header,
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},
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},
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}};
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i = subtemplate.new_idx;
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},
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.switch_header => |header| {
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var cases: []const Case = &.{};
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var else_branch: ?[]const TemplateItem = null;
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var last_header: CaseHeader = header.first_case;
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var is_else = false;
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while (true) {
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const case = parseTemplate(tokens, i + 1, .switch_block);
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i = case.new_idx;
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if (!is_else) {
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cases = cases ++ [_]Case{.{
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.header = last_header,
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.subtemplate = case.items,
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}};
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} else {
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else_branch = case.items;
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}
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switch (case.closing_block.?.block) {
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.end_switch => break,
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.@"else" => is_else = true,
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.case_header => |case_header| last_header = case_header,
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else => @compileError("Unexpected token"),
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}
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}
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items = items ++ [_]TemplateItem{.{
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.statement = .{
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.@"switch" = .{
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.expression = header.expression,
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.cases = cases,
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.else_branch = else_branch,
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},
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},
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}};
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},
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.end_for => if (template_type == .for_block)
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break cb
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else
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@compileError("Unexpected /for tag"),
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.end_if => if (template_type == .if_block or template_type == .if_else_block)
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break cb
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else
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@compileError("Unexpected /if tag"),
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.elif_header => if (template_type == .if_block)
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break cb
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else
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@compileError("Unexpected #elif tag"),
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.@"else" => if (template_type == .if_block or template_type == .switch_block)
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break cb
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else
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@compileError("Unexpected #else tag"),
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.call_template => |call| items = items ++ [_]TemplateItem{.{
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.statement = .{ .call_template = call },
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}},
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.end_switch, .case_header => if (template_type == .switch_block)
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break cb
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else
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@compileError("Unexpected /switch tag"),
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}
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},
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}
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} else null;
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if (current_text.len != 0) items = items ++ [_]TemplateItem{.{ .text = current_text }};
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|
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if (template_type != .root and closing_block == null) @compileError("End tag not found");
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|
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return .{
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.new_idx = i,
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.items = items,
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.closing_block = closing_block,
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};
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}
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}
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|
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const TemplateToken = union(enum) {
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text: []const u8,
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whitespace: []const u8,
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control_block: ControlBlock,
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};
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|
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fn parseTemplateTokens(comptime tokens: ControlTokenIter) []const TemplateToken {
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comptime {
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var iter = tokens;
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var items: []const TemplateToken = &.{};
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|
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while (iter.next()) |token| switch (token) {
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.whitespace => |wsp| items = items ++ [_]TemplateToken{.{ .whitespace = wsp }},
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.text => |text| items = items ++ [_]TemplateToken{.{ .text = text }},
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.open_bracket => {
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const next = iter.next() orelse @compileError("Unexpected end of template");
|
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if (next == .open_bracket) {
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items = items ++ [_]TemplateToken{.{ .text = "{" }};
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} else {
|
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iter.putBack(next);
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const result = parseControlBlock(iter);
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iter = result.new_iter;
|
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items = items ++ [_]TemplateToken{.{ .control_block = result.item }};
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}
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},
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.close_bracket => {
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const next = iter.next() orelse @compileError("Unexpected end of template");
|
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if (next == .close_bracket)
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items = items ++ [_]TemplateToken{.{ .text = "}" }}
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else
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@compileError("Unpaired close bracket, did you mean \"}}\"?");
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},
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.period => items = items ++ [_]TemplateToken{.{ .text = "." }},
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.pound => items = items ++ [_]TemplateToken{.{ .text = "#" }},
|
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.pipe => items = items ++ [_]TemplateToken{.{ .text = "|" }},
|
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.dollar => items = items ++ [_]TemplateToken{.{ .text = "$" }},
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.slash => items = items ++ [_]TemplateToken{.{ .text = "/" }},
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.equals => items = items ++ [_]TemplateToken{.{ .text = "=" }},
|
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.at => items = items ++ [_]TemplateToken{.{ .text = "@" }},
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.comma => items = items ++ [_]TemplateToken{.{ .text = "," }},
|
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.percent => items = items ++ [_]TemplateToken{.{ .text = "%" }},
|
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.open_paren => items = items ++ [_]TemplateToken{.{ .text = "(" }},
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.close_paren => items = items ++ [_]TemplateToken{.{ .text = ")" }},
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};
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|
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return items;
|
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}
|
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}
|
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|
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fn parseExpression(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, Expression) {
|
|
comptime {
|
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var iter = tokens;
|
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|
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var last_valid_iter: ?ControlTokenIter = null;
|
|
var expr: ?Expression = null;
|
|
while (iter.next()) |token| switch (token) {
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|
.whitespace => {},
|
|
.period => {
|
|
const names = parseDeref(iter);
|
|
iter = names.new_iter;
|
|
if (expr != null) break;
|
|
expr = .{ .arg_deref = names.item };
|
|
last_valid_iter = iter;
|
|
},
|
|
.dollar => {
|
|
const names = parseDeref(iter);
|
|
iter = names.new_iter;
|
|
if (expr != null) break;
|
|
expr = .{ .capture_deref = names.item };
|
|
last_valid_iter = iter;
|
|
},
|
|
.percent => {
|
|
const names = parseDeref(iter);
|
|
iter = names.new_iter;
|
|
if (expr != null) break;
|
|
expr = .{ .context_deref = names.item };
|
|
last_valid_iter = iter;
|
|
},
|
|
.equals => {
|
|
const next = iter.next() orelse break;
|
|
if (next == .equals) {
|
|
const lhs = expr orelse break;
|
|
const rhs = parseExpression(iter);
|
|
iter = rhs.new_iter;
|
|
|
|
expr = .{
|
|
.equals = &.{
|
|
.lhs = lhs,
|
|
.rhs = rhs.item,
|
|
},
|
|
};
|
|
last_valid_iter = iter;
|
|
} else break;
|
|
},
|
|
.at => {
|
|
if (expr != null) break;
|
|
const builtin = parseBuiltin(iter);
|
|
iter = builtin.new_iter;
|
|
expr = .{ .builtin = &builtin.item };
|
|
last_valid_iter = iter;
|
|
},
|
|
else => break,
|
|
};
|
|
|
|
return .{
|
|
.new_iter = last_valid_iter orelse @compileError("Invalid Expression"),
|
|
.item = expr orelse @compileError("Invalid Expression"),
|
|
};
|
|
}
|
|
}
|
|
|
|
fn expectToken(comptime token: ?ControlToken, comptime exp: std.meta.Tag(ControlToken)) void {
|
|
comptime {
|
|
if (token == null) @compileError("Unexpected End Of Template");
|
|
const token_tag = std.meta.activeTag(token.?);
|
|
|
|
if (token_tag != exp)
|
|
@compileError("Expected " ++ @tagName(exp) ++ ", got " ++ @tagName(token_tag));
|
|
}
|
|
}
|
|
|
|
fn parseBuiltin(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, BuiltinCall) {
|
|
comptime {
|
|
var iter = tokens;
|
|
const builtin = blk: {
|
|
const next = iter.next() orelse @compileError("Invalid Builtin");
|
|
if (next != .text) @compileError("Invalid Builtin");
|
|
break :blk std.meta.stringToEnum(Builtin, next.text) orelse @compileError("Invalid Builtin");
|
|
};
|
|
|
|
iter = skipWhitespace(iter);
|
|
expectToken(iter.next(), .open_paren);
|
|
iter = skipWhitespace(iter);
|
|
const call = switch (builtin) {
|
|
.isTag => blk: {
|
|
const expr = parseExpression(iter);
|
|
iter = expr.new_iter;
|
|
expectToken(iter.next(), .comma);
|
|
iter = skipWhitespace(iter);
|
|
const tag = iter.next();
|
|
expectToken(tag, .text);
|
|
break :blk .{
|
|
.isTag = .{
|
|
.tag = tag.?.text,
|
|
.expression = expr.item,
|
|
},
|
|
};
|
|
},
|
|
};
|
|
iter = skipWhitespace(iter);
|
|
expectToken(iter.next(), .close_paren);
|
|
|
|
return .{
|
|
.new_iter = iter,
|
|
.item = call,
|
|
};
|
|
}
|
|
}
|
|
|
|
fn parseControlBlock(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, ControlBlock) {
|
|
comptime {
|
|
var iter = tokens;
|
|
|
|
const strip_before = if (iter.next()) |first| blk: {
|
|
if (first == .equals) {
|
|
break :blk true;
|
|
}
|
|
|
|
iter.putBack(first);
|
|
break :blk false;
|
|
} else @compileError("Unexpected end of template");
|
|
|
|
var stmt: ControlBlock.Data = while (iter.next()) |token| switch (token) {
|
|
.equals => @compileError("Unexpected '='"),
|
|
.whitespace => {},
|
|
.pound => {
|
|
const next = iter.next() orelse @compileError("Unexpected end of template");
|
|
if (next != .text) @compileError("Expected keyword following '#' character");
|
|
const text = next.text;
|
|
const keyword = std.meta.stringToEnum(Keyword, text) orelse @compileError("Unknown keyword: " ++ text);
|
|
|
|
switch (keyword) {
|
|
.@"for" => {
|
|
const result = parseForHeader(iter);
|
|
iter = result.new_iter;
|
|
break .{ .for_header = result.item };
|
|
},
|
|
.@"if" => {
|
|
const result = parseIfHeader(iter);
|
|
iter = result.new_iter;
|
|
break .{ .if_header = result.item };
|
|
},
|
|
.@"else" => break .{ .@"else" = {} },
|
|
.@"elif" => {
|
|
const result = parseIfHeader(iter);
|
|
iter = result.new_iter;
|
|
break .{ .elif_header = result.item };
|
|
},
|
|
.template => {
|
|
const result = parseCallTemplate(iter);
|
|
iter = result.new_iter;
|
|
break .{ .call_template = result.item };
|
|
},
|
|
.@"switch" => {
|
|
const result = parseSwitchHeader(iter);
|
|
iter = result.new_iter;
|
|
break .{ .switch_header = result.item };
|
|
},
|
|
.case => {
|
|
const result = parseCaseHeader(iter);
|
|
iter = result.new_iter;
|
|
break .{ .case_header = result.item };
|
|
},
|
|
|
|
//else => @compileError("TODO"),
|
|
}
|
|
},
|
|
.slash => {
|
|
const next = iter.next() orelse @compileError("Unexpected end of template");
|
|
if (next != .text) @compileError("Expected keyword following '/' character");
|
|
const text = next.text;
|
|
const keyword = std.meta.stringToEnum(EndKeyword, text) orelse @compileError("Unknown keyword: " ++ text);
|
|
|
|
switch (keyword) {
|
|
.@"for" => break .{ .end_for = {} },
|
|
.@"if" => break .{ .end_if = {} },
|
|
.@"switch" => break .{ .end_switch = {} },
|
|
}
|
|
},
|
|
.period, .dollar, .percent => {
|
|
iter.putBack(token);
|
|
const expr = parseExpression(iter);
|
|
iter = expr.new_iter;
|
|
break .{ .expression = expr.item };
|
|
},
|
|
else => @compileError("TODO"),
|
|
};
|
|
|
|
// search for end of statement
|
|
var strip_after: bool = false;
|
|
while (iter.next()) |token| switch (token) {
|
|
.whitespace => {},
|
|
.equals => {
|
|
if (iter.peek()) |t| {
|
|
if (t == .close_bracket) {
|
|
strip_after = true;
|
|
continue;
|
|
}
|
|
}
|
|
@compileError("Unexpected '='");
|
|
},
|
|
.close_bracket => return .{
|
|
.new_iter = iter,
|
|
.item = .{
|
|
.block = stmt,
|
|
.strip_before = strip_before,
|
|
.strip_after = strip_after,
|
|
},
|
|
},
|
|
else => {
|
|
@compileLog(iter.row);
|
|
@compileError("TODO " ++ @tagName(token) ++ " " ++ token.text);
|
|
},
|
|
};
|
|
|
|
@compileError("Unexpected end of template");
|
|
}
|
|
}
|
|
|
|
fn skipWhitespace(comptime tokens: ControlTokenIter) ControlTokenIter {
|
|
comptime {
|
|
var iter = tokens;
|
|
while (iter.peek()) |token| switch (token) {
|
|
.whitespace => _ = iter.next(),
|
|
else => break,
|
|
};
|
|
|
|
return iter;
|
|
}
|
|
}
|
|
|
|
fn endControlBlock(comptime tokens: ControlTokenIter) ControlTokenIter {
|
|
comptime {
|
|
var iter = skipWhitespace(tokens);
|
|
|
|
const token = iter.next() orelse @compileError("Unexpected end of template");
|
|
if (token != .close_bracket) @compileError("Unexpected token");
|
|
return iter;
|
|
}
|
|
}
|
|
|
|
fn parseForHeader(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, ForHeader) {
|
|
comptime {
|
|
const iterable = parseExpression(tokens);
|
|
var iter = iterable.new_iter;
|
|
|
|
iter = skipWhitespace(iter);
|
|
{
|
|
const token = iter.next() orelse @compileError("Unexpected end of template");
|
|
if (token != .pipe) @compileError("Unexpected token");
|
|
}
|
|
{
|
|
const token = iter.next() orelse @compileError("Unexpected end of template");
|
|
if (token != .dollar) @compileError("Unexpected token");
|
|
}
|
|
const capture = blk: {
|
|
const token = iter.next() orelse @compileError("Unexpected end of template");
|
|
if (token != .text) @compileError("Unexpected token");
|
|
break :blk token.text;
|
|
};
|
|
{
|
|
const token = iter.next() orelse @compileError("Unexpected end of template");
|
|
if (token != .pipe) @compileError("Unexpected token");
|
|
}
|
|
|
|
return .{
|
|
.new_iter = iter,
|
|
.item = .{
|
|
.iterable = iterable.item,
|
|
.capture = capture,
|
|
},
|
|
};
|
|
}
|
|
}
|
|
|
|
fn tryParseCapture(comptime tokens: ControlTokenIter) ?ParseResult(ControlTokenIter, []const []const u8) {
|
|
comptime {
|
|
var iter = tokens;
|
|
|
|
iter = skipWhitespace(iter);
|
|
if ((iter.next() orelse return null) != .pipe) return null;
|
|
var captures: []const []const u8 = &.{};
|
|
while (true) {
|
|
iter = skipWhitespace(iter);
|
|
if ((iter.next() orelse return null) != .dollar) return null;
|
|
iter = skipWhitespace(iter);
|
|
const name = switch (iter.next() orelse return null) {
|
|
.text => |text| text,
|
|
else => return null,
|
|
};
|
|
iter = skipWhitespace(iter);
|
|
captures = captures ++ &[_][]const u8{name};
|
|
|
|
switch (iter.next() orelse return null) {
|
|
.pipe => break,
|
|
.comma => {},
|
|
else => return null,
|
|
}
|
|
}
|
|
|
|
return .{
|
|
.new_iter = iter,
|
|
.item = captures,
|
|
};
|
|
}
|
|
}
|
|
|
|
fn parseIfHeader(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, IfHeader) {
|
|
comptime {
|
|
const condition = parseExpression(tokens);
|
|
var iter = condition.new_iter;
|
|
|
|
const captures = tryParseCapture(iter);
|
|
if (captures) |cap| {
|
|
if (cap.item.len == 1) {
|
|
return .{
|
|
.new_iter = cap.new_iter,
|
|
.item = IfHeader{
|
|
.condition = condition.item,
|
|
.capture = cap.item[0],
|
|
},
|
|
};
|
|
} else @compileError("Only one capture allowed for if statements");
|
|
}
|
|
|
|
return .{
|
|
.new_iter = iter,
|
|
.item = .{
|
|
.condition = condition.item,
|
|
.capture = null,
|
|
},
|
|
};
|
|
}
|
|
}
|
|
|
|
fn parseCaseHeader(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, CaseHeader) {
|
|
comptime {
|
|
var iter = skipWhitespace(tokens);
|
|
const tag = iter.next();
|
|
expectToken(tag, .text);
|
|
|
|
const captures = tryParseCapture(iter);
|
|
if (captures) |cap| {
|
|
if (cap.item.len == 1) {
|
|
return .{
|
|
.new_iter = cap.new_iter,
|
|
.item = CaseHeader{
|
|
.tag = tag.?.text,
|
|
.capture = cap.item[0],
|
|
},
|
|
};
|
|
} else @compileError("Only one capture allowed for case statements");
|
|
}
|
|
|
|
return .{
|
|
.new_iter = iter,
|
|
.item = .{
|
|
.tag = tag.?.text,
|
|
.capture = null,
|
|
},
|
|
};
|
|
}
|
|
}
|
|
|
|
fn parseSwitchHeader(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, SwitchHeader) {
|
|
comptime {
|
|
const condition = parseExpression(tokens);
|
|
var iter = skipWhitespace(condition.new_iter);
|
|
|
|
const next = iter.next();
|
|
expectToken(next, .text);
|
|
if (!std.mem.eql(u8, next.?.text, "case")) @compileError("Expected case following switch condition");
|
|
|
|
iter = skipWhitespace(iter);
|
|
const first = parseCaseHeader(iter);
|
|
|
|
return .{
|
|
.new_iter = first.new_iter,
|
|
.item = .{
|
|
.expression = condition.item,
|
|
.first_case = first.item,
|
|
},
|
|
};
|
|
}
|
|
}
|
|
|
|
fn parseDeref(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, []const []const u8) {
|
|
comptime {
|
|
var iter = tokens;
|
|
var fields: []const []const u8 = &.{};
|
|
var wants = .text;
|
|
while (iter.peek()) |token| {
|
|
switch (token) {
|
|
.whitespace => {},
|
|
.text => |text| {
|
|
if (wants == .period) break;
|
|
fields = fields ++ [1][]const u8{text};
|
|
wants = .period;
|
|
},
|
|
.period => {
|
|
if (wants != .period) @compileError("Unexpected token \".\"");
|
|
wants = .text;
|
|
},
|
|
else => if (wants == .period or fields.len == 0) break else @compileError("Unexpected token"),
|
|
}
|
|
_ = iter.next();
|
|
}
|
|
|
|
return .{
|
|
.new_iter = iter,
|
|
.item = fields,
|
|
};
|
|
}
|
|
}
|
|
|
|
fn parseCallTemplate(comptime tokens: ControlTokenIter) ParseResult(ControlTokenIter, CallTemplate) {
|
|
comptime {
|
|
var iter = tokens;
|
|
const template_name = while (iter.next()) |token| switch (token) {
|
|
.text => |t| break t,
|
|
.whitespace => {},
|
|
else => @compileError("Unexpected token"),
|
|
} else @compileError("Unexpected end of template");
|
|
|
|
const args = parseExpression(iter);
|
|
|
|
return .{
|
|
.new_iter = args.new_iter,
|
|
.item = .{
|
|
.template_name = template_name,
|
|
.args = args.item,
|
|
},
|
|
};
|
|
}
|
|
}
|
|
|
|
fn ParseResult(comptime It: type, comptime T: type) type {
|
|
return struct {
|
|
new_iter: It,
|
|
item: T,
|
|
};
|
|
}
|
|
|
|
const TemplateItem = union(enum) {
|
|
text: []const u8,
|
|
statement: Statement,
|
|
};
|
|
|
|
const EqualsExpr = struct {
|
|
lhs: Expression,
|
|
rhs: Expression,
|
|
};
|
|
|
|
const Expression = union(enum) {
|
|
arg_deref: []const []const u8,
|
|
capture_deref: []const []const u8,
|
|
context_deref: []const []const u8,
|
|
equals: *const EqualsExpr,
|
|
builtin: *const BuiltinCall,
|
|
};
|
|
|
|
const For = struct {
|
|
subtemplate: []const TemplateItem,
|
|
header: ForHeader,
|
|
};
|
|
|
|
const ForHeader = struct {
|
|
iterable: Expression,
|
|
capture: []const u8,
|
|
};
|
|
|
|
const If = struct {
|
|
subtemplate: []const TemplateItem,
|
|
header: IfHeader,
|
|
else_branch: ?union(enum) {
|
|
@"else": []const TemplateItem,
|
|
elif: *const If,
|
|
},
|
|
};
|
|
|
|
const Case = struct {
|
|
header: CaseHeader,
|
|
subtemplate: []const TemplateItem,
|
|
};
|
|
|
|
const SwitchHeader = struct {
|
|
expression: Expression,
|
|
first_case: CaseHeader,
|
|
};
|
|
|
|
const CaseHeader = struct {
|
|
tag: []const u8,
|
|
capture: ?[]const u8,
|
|
};
|
|
|
|
const Switch = struct {
|
|
expression: Expression,
|
|
cases: []const Case,
|
|
else_branch: ?[]const TemplateItem,
|
|
};
|
|
|
|
const CallTemplate = struct {
|
|
template_name: []const u8,
|
|
args: Expression,
|
|
};
|
|
|
|
const IfHeader = struct {
|
|
condition: Expression,
|
|
capture: ?[]const u8,
|
|
};
|
|
|
|
const Statement = union(enum) {
|
|
expression: Expression,
|
|
@"for": For,
|
|
@"if": If,
|
|
@"switch": Switch,
|
|
call_template: CallTemplate,
|
|
};
|
|
|
|
const ControlBlock = struct {
|
|
const Data = union(enum) {
|
|
expression: Expression,
|
|
for_header: ForHeader,
|
|
end_for: void,
|
|
if_header: IfHeader,
|
|
end_if: void,
|
|
@"else": void,
|
|
elif_header: IfHeader,
|
|
call_template: CallTemplate,
|
|
switch_header: SwitchHeader,
|
|
case_header: CaseHeader,
|
|
end_switch: void,
|
|
};
|
|
block: Data,
|
|
strip_before: bool,
|
|
strip_after: bool,
|
|
};
|
|
|
|
const Keyword = enum {
|
|
@"for",
|
|
@"if",
|
|
@"else",
|
|
@"elif",
|
|
@"template",
|
|
@"switch",
|
|
@"case",
|
|
};
|
|
|
|
const EndKeyword = enum {
|
|
@"for",
|
|
@"if",
|
|
@"switch",
|
|
};
|
|
|
|
const Builtin = enum {
|
|
isTag,
|
|
};
|
|
|
|
const BuiltinCall = union(Builtin) {
|
|
isTag: struct {
|
|
tag: []const u8,
|
|
expression: Expression,
|
|
},
|
|
};
|
|
|
|
const ControlToken = union(enum) {
|
|
text: []const u8,
|
|
open_bracket: void,
|
|
close_bracket: void,
|
|
period: void,
|
|
whitespace: []const u8,
|
|
pound: void,
|
|
pipe: void,
|
|
dollar: void,
|
|
slash: void,
|
|
equals: void,
|
|
at: void,
|
|
comma: void,
|
|
percent: void,
|
|
open_paren: void,
|
|
close_paren: void,
|
|
};
|
|
|
|
const ControlTokenIter = struct {
|
|
start: usize = 0,
|
|
text: []const u8,
|
|
peeked_token: ?ControlToken = null,
|
|
|
|
row: usize = 0,
|
|
|
|
fn next(self: *ControlTokenIter) ?ControlToken {
|
|
if (self.peeked_token) |token| {
|
|
self.peeked_token = null;
|
|
return token;
|
|
}
|
|
|
|
const remaining = self.text[self.start..];
|
|
if (remaining.len == 0) return null;
|
|
|
|
const ch = remaining[0];
|
|
self.start += 1;
|
|
switch (ch) {
|
|
'{' => return .{ .open_bracket = {} },
|
|
'}' => return .{ .close_bracket = {} },
|
|
'.' => return .{ .period = {} },
|
|
'#' => return .{ .pound = {} },
|
|
'|' => return .{ .pipe = {} },
|
|
'$' => return .{ .dollar = {} },
|
|
'/' => return .{ .slash = {} },
|
|
'=' => return .{ .equals = {} },
|
|
'@' => return .{ .at = {} },
|
|
',' => return .{ .comma = {} },
|
|
'%' => return .{ .percent = {} },
|
|
'(' => return .{ .open_paren = {} },
|
|
')' => return .{ .close_paren = {} },
|
|
' ', '\t', '\n', '\r' => {
|
|
var idx: usize = 0;
|
|
while (idx < remaining.len and std.mem.indexOfScalar(u8, " \t\n\r", remaining[idx]) != null) : (idx += 1) {}
|
|
const newline_count = std.mem.count(u8, remaining[0..idx], "\n");
|
|
self.row += newline_count;
|
|
|
|
self.start += idx - 1;
|
|
return .{ .whitespace = remaining[0..idx] };
|
|
},
|
|
else => {
|
|
var idx: usize = 0;
|
|
while (idx < remaining.len and std.mem.indexOfScalar(u8, "{}.#|$/=@,%() \t\n\r", remaining[idx]) == null) : (idx += 1) {}
|
|
|
|
self.start += idx - 1;
|
|
return .{ .text = remaining[0..idx] };
|
|
},
|
|
}
|
|
}
|
|
|
|
fn peek(self: *ControlTokenIter) ?ControlToken {
|
|
const token = self.next();
|
|
self.peeked_token = token;
|
|
return token;
|
|
}
|
|
|
|
fn putBack(self: *ControlTokenIter, token: ControlToken) void {
|
|
std.debug.assert(self.peeked_token == null);
|
|
self.peeked_token = token;
|
|
}
|
|
};
|
|
|
|
test "template" {
|
|
const testCase = struct {
|
|
fn case(comptime tmpl: []const u8, args: anytype, expected: []const u8) !void {
|
|
var stream = std.io.changeDetectionStream(expected, std.io.null_writer);
|
|
try execute(stream.writer(), .{}, tmpl, args, .{});
|
|
try std.testing.expect(!stream.changeDetected());
|
|
}
|
|
}.case;
|
|
|
|
try testCase("", .{}, "");
|
|
try testCase("abcd", .{}, "abcd");
|
|
try testCase("{.val}", .{ .val = 3 }, "3");
|
|
try testCase("{#if .val}1{/if}", .{ .val = true }, "1");
|
|
try testCase("{#for .vals |$v|}{$v}{/for}", .{ .vals = [_]u8{ 1, 2, 3 } }, "123");
|
|
try testCase("{#for .vals |$v|=} {$v} {=/for}", .{ .vals = [_]u8{ 1, 2, 3 } }, "123");
|
|
try testCase("{#if .val}1{#else}0{/if}", .{ .val = true }, "1");
|
|
try testCase("{#if .val}1{#else}0{/if}", .{ .val = false }, "0");
|
|
try testCase("{#if .val}1{#elif .foo}2{/if}", .{ .val = false, .foo = true }, "2");
|
|
try testCase("{#if .val}1{#elif .foo}2{/if}", .{ .val = false, .foo = false }, "");
|
|
try testCase("{#if .val}1{#elif .foo}2{#else}0{/if}", .{ .val = false, .foo = false }, "0");
|
|
try testCase("{#if .val}1{#elif .foo}2{#else}0{/if}", .{ .val = true, .foo = false }, "1");
|
|
try testCase("{#if .val}1{#elif .foo}2{#else}0{/if}", .{ .val = false, .foo = true }, "2");
|
|
try testCase("{#if .val}1{#elif .foo}2{#else}0{/if}", .{ .val = true, .foo = true }, "1");
|
|
}
|