From 7191ad8f27b47fc224222771097dcff30ab03c65 Mon Sep 17 00:00:00 2001 From: jaina heartles Date: Tue, 15 Nov 2022 22:07:45 -0800 Subject: [PATCH] Split up template parsing and execution --- src/template/lib.zig | 170 +++++++++++++++++++++++++++---------- src/template/test.tmp.html | 5 +- 2 files changed, 130 insertions(+), 45 deletions(-) diff --git a/src/template/lib.zig b/src/template/lib.zig index fb20ec4..7cf23d6 100644 --- a/src/template/lib.zig +++ b/src/template/lib.zig @@ -4,63 +4,141 @@ pub fn main() !void { try execute(std.io.getStdOut().writer(), @embedFile("./test.tmp.html"), .{ .community = .{ .name = "abcd" } }); } +const logging = false; + pub fn execute(writer: anytype, comptime template: []const u8, args: anytype) !void { @setEvalBranchQuota(@intCast(u32, template.len * 6)); comptime var iter = TokenIter{ .text = template }; - comptime var state: State = .text; inline while (comptime iter.next()) |token| { + if (logging) @compileLog(token); switch (token) { - .text => |text| switch (state) { - .text => try writer.writeAll(text), - else => @compileError("Text token not allowed in state " ++ @tagName(state) ++ text), - }, - .open_bracket => switch (state) { - .text => state = .template_start, - .template_start => { + .text => |text| try writer.writeAll(text), + .open_bracket => { + const next = comptime iter.peek() orelse @compileError("Unexpected end of template"); + if (next == .open_bracket) { try writer.writeByte('{'); - state = .text; - }, - else => @compileError(""), + _ = comptime iter.next(); + } else { + const result = comptime parseStatement(iter); + try executeStatement(writer, result.statement, args); + iter = result.new_iter; + } }, - .close_bracket => switch (state) { - .text => state = .text_close_bracket, - .text_close_bracket => { - try writer.writeByte('}'); - state = .text; - }, - .template_start, .template => state = .text, - //else => @compileError(""), - }, - .whitespace => |wsp| switch (state) { - .text => try writer.writeAll(wsp), - else => {}, - }, - .period => switch (state) { - .text => try writer.writeByte('.'), - .template_start, .template => { - try argDeref(writer, &iter, args); - state = .template; - }, - else => @compileError(""), + .close_bracket => { + const next = comptime iter.next() orelse @compileError("Unexpected end of template"); + if (comptime next == .close_bracket) try writer.writeByte('}') else @compileError("Unpaired close bracket, did you mean \"}}\"?"); }, + .whitespace => |wsp| try writer.writeAll(wsp), + .period => try writer.writeByte('.'), + .pound => try writer.writeByte('#'), } } } -fn argDeref(writer: anytype, comptime iter: *TokenIter, arg: anytype) !void { - inline while (comptime iter.peek()) |token| { - switch (token) { - .period => {}, - .text => |text| { - _ = comptime iter.next(); - return argDeref(writer, iter, @field(arg, text)); - }, - else => return try writer.writeAll(arg), - } - _ = comptime iter.next(); +fn executeStatement(writer: anytype, comptime stmt: Statement, args: anytype) !void { + switch (stmt) { + .expression => |expr| switch (expr) { + .arg_deref => |fields| try argDeref(writer, fields, args), + }, + else => @compileError("TODO"), } } +fn argDeref(writer: anytype, comptime names: []const []const u8, arg: anytype) !void { + if (names.len == 0) { + const T = @TypeOf(arg); + if (comptime std.meta.trait.isZigString(T)) return writer.writeAll(arg); + return std.fmt.format(writer, "{any}", .{arg}); + } + + return argDeref(writer, names[1..], @field(arg, names[0])); +} + +fn parseStatement(comptime tokens: TokenIter) StatementResult { + comptime { + var iter = tokens; + while (iter.next()) |token| switch (token) { + .whitespace => {}, + .pound => { + const next = iter.next() orelse @compileError("Unexpected end of template"); + if (logging) @compileLog("keyword", next); + if (next != .text) @compileError("Expected keyword following '#' character"); + const text = next.text; + const keyword = std.meta.stringToEnum(Keyword, text) orelse @compileError("Unknown keyword: " ++ text); + + _ = keyword; + @panic("todo"); + }, + .period => { + const expr = parseArgDeref(iter); + iter = expr.new_iter; + while (iter.next()) |it| switch (it) { + .whitespace => {}, + .close_bracket => break, + else => @compileError("TODO"), + }; + return .{ .new_iter = iter, .statement = .{ + .expression = expr.expression, + } }; + }, + else => @compileError(""), + }; + + @compileError("Unexpected end of template"); + } +} + +fn parseArgDeref(comptime tokens: TokenIter) ExpressionResult { + comptime { + var iter = tokens; + var fields: []const []const u8 = &.{}; + var wants = .text; + while (iter.peek()) |token| { + switch (token) { + .whitespace => {}, + .text => |text| { + if (wants != .text) @compileError("Unexpected token \"" ++ text ++ "\""); + fields = fields ++ [1][]const u8{text}; + wants = .period; + }, + .period => { + if (wants != .period) @compileError("Unexpected token \".\""); + wants = .text; + }, + else => if (wants == .period) return .{ + .new_iter = iter, + .expression = .{ .arg_deref = fields }, + } else @compileError("Unexpected token"), + } + _ = iter.next(); + } + } +} + +const Expression = union(enum) { + arg_deref: []const []const u8, +}; + +const ExpressionResult = struct { + new_iter: TokenIter, + expression: Expression, +}; + +const Statement = union(enum) { + expression: Expression, + for_loop: struct { + subtemplate: []const u8, + indexable: Expression, + iteration_capture: []const u8, + index_capture: ?[]const u8, + }, +}; + +const StatementResult = struct { + new_iter: TokenIter, + statement: Statement, +}; + const State = enum { text, text_close_bracket, @@ -68,12 +146,17 @@ const State = enum { template, }; +const Keyword = enum { + @"for", +}; + const Token = union(enum) { text: []const u8, open_bracket: void, close_bracket: void, period: void, whitespace: []const u8, + pound: void, }; const TokenIter = struct { @@ -96,6 +179,7 @@ const TokenIter = struct { '{' => return .{ .open_bracket = {} }, '}' => return .{ .close_bracket = {} }, '.' => return .{ .period = {} }, + '#' => return .{ .pound = {} }, ' ', '\t', '\n', '\r' => { var idx: usize = 0; while (idx < remaining.len and std.mem.indexOfScalar(u8, " \t\n\r", remaining[idx]) != null) : (idx += 1) {} @@ -105,7 +189,7 @@ const TokenIter = struct { }, else => { var idx: usize = 0; - while (idx < remaining.len and std.mem.indexOfScalar(u8, "{}. \t\n\r", remaining[idx]) == null) : (idx += 1) {} + 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] }; diff --git a/src/template/test.tmp.html b/src/template/test.tmp.html index 9c2ce7b..503b619 100644 --- a/src/template/test.tmp.html +++ b/src/template/test.tmp.html @@ -1,7 +1,7 @@ - { .community.name } + {.community.name} @@ -9,10 +9,11 @@

{{ REAL BRACKETS }}

+ {{#for .community}} {{#for args.notes |$note, $i|}}

Note no. {{$i}}

{{#template note_display ($note)}} - {{/for}} + {{#end}}