add if statements

This commit is contained in:
Luna 2019-08-25 13:02:40 -03:00
parent 83910811fa
commit 9b3e9e8139
3 changed files with 99 additions and 14 deletions

View file

@ -11,4 +11,10 @@ fn main(a int) int {
3 / (51 + 2)
mut a := 1+2
a = 2
if a {
println(30)
} else {
println(50)
}
}

View file

@ -88,12 +88,12 @@ pub const Expr = union(ExprType) {
Grouping: *Expr,
};
pub const IfBranch = std.ArrayList(Stmt);
pub const IfBranch = std.ArrayList(*Stmt);
pub const IfStmt = struct {
condition: *Expr,
then_branch: IfBranch,
else_branch: IfBranch,
else_branch: ?IfBranch,
};
pub const Stmt = union(enum) {
@ -107,6 +107,23 @@ pub const Stmt = union(enum) {
println.* = Stmt{ .Println = expr };
return println;
}
pub fn mkIfStmt(
allocator: *std.mem.Allocator,
condition: *Expr,
then: IfBranch,
else_branch: ?IfBranch,
) !*Stmt {
var println = try allocator.create(Stmt);
println.* = Stmt{
.If = IfStmt{
.condition = condition,
.then_branch = then,
.else_branch = else_branch,
},
};
return println;
}
};
pub const Node = union(NodeType) {
@ -138,6 +155,22 @@ fn print(ident: usize, comptime fmt: []const u8, args: ...) void {
std.debug.warn(fmt, args);
}
fn printBlock(ident: usize, block: var, endNewline: bool) void {
std.debug.warn("(\n");
for (block.toSlice()) |stmt| {
printIdent(ident);
printStmt(ident, stmt);
std.debug.warn("\n");
}
if (endNewline) {
print(ident - 1, ")\n");
} else {
print(ident - 1, ")");
}
}
pub fn printNode(node: *Node, ident: usize) void {
switch (node.*) {
.FnDecl => |decl| {
@ -147,15 +180,8 @@ pub fn printNode(node: *Node, ident: usize) void {
std.debug.warn("({} {}) ", param.name.lexeme, param.typ.lexeme);
}
std.debug.warn(") (\n");
for (decl.body.toSlice()) |stmt| {
printIdent(ident + 1);
printStmt(stmt);
std.debug.warn("\n");
}
print(ident, ")\n");
printBlock(ident + 1, decl.body, false);
std.debug.warn(")\n");
},
.ConstDecl => |consts| {
@ -189,7 +215,7 @@ pub fn printNode(node: *Node, ident: usize) void {
.Stmt => |stmt| blk: {
printIdent(ident);
printStmt(stmt);
printStmt(ident, stmt);
std.debug.warn("\n");
},
@ -250,10 +276,24 @@ pub fn printExpr(expr: *Expr) void {
}
}
pub fn printStmt(stmt: *Stmt) void {
pub fn printStmt(ident: usize, stmt: *Stmt) void {
switch (stmt.*) {
.Println => |expr| parenthetize("println", &[_]*Expr{expr}),
.Expr => |expr| printExpr(expr),
.If => |ifstmt| {
std.debug.warn("(if ");
printExpr(ifstmt.condition);
std.debug.warn(" ");
printBlock(ident + 1, ifstmt.then_branch, false);
if (ifstmt.else_branch) |else_branch| {
std.debug.warn(" else ");
printBlock(ident + 1, else_branch, false);
}
std.debug.warn(")\n");
},
else => std.debug.warn("UnknownStmt-{}", @tagName(stmt.*)),
}
}

View file

@ -419,7 +419,6 @@ pub const Parser = struct {
_ = try self.consumeSingle(.LeftBrace);
while (self.peek().ttype != .RightBrace) {
std.debug.warn("get smt with cur {}\n", self.peek().ttype);
var stmt = try self.parseDecl();
ast.printNode(try self.mkStmt(stmt), 0);
try stmts.append(stmt);
@ -436,6 +435,7 @@ pub const Parser = struct {
fn parseStmt(self: *@This()) anyerror!*Stmt {
return switch (self.peek().ttype) {
.If => try self.parseIfStmt(),
.Println => try self.parsePrintln(),
// TODO make newlines tokens and consume newline?
@ -443,6 +443,45 @@ pub const Parser = struct {
};
}
/// Copy of parseBlock for if branches
fn parseIfBranch(self: *@This()) !ast.IfBranch {
var branch = ast.IfBranch.init(self.allocator);
errdefer branch.deinit();
_ = try self.consumeSingle(.LeftBrace);
while (self.peek().ttype != .RightBrace) {
var stmt = try self.parseDecl();
ast.printNode(try self.mkStmt(stmt), 0);
try branch.append(stmt);
}
_ = try self.consumeSingle(.RightBrace);
return branch;
}
fn parseIfStmt(self: *@This()) !*Stmt {
_ = try self.consumeSingle(.If);
var condition = (try self.parseExpr()).Expr;
const then_branch = try self.parseIfBranch();
var else_branch: ?ast.IfBranch = null;
if (self.check(.Else)) {
_ = try self.consumeSingle(.Else);
else_branch = try self.parseIfBranch();
}
return try Stmt.mkIfStmt(
self.allocator,
condition,
then_branch,
else_branch,
);
}
fn parsePrintln(self: *@This()) !*Stmt {
_ = try self.consumeSingle(.Println);