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std.zig.parser understands inferred return type and error inference

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This commit is contained in:
Andrew Kelley 2018-02-14 15:48:15 -05:00
parent e8d81c5acf
commit 629f134d38
2 changed files with 83 additions and 18 deletions
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22
std/zig/ast.zig
View File

@ -102,7 +102,7 @@ pub const NodeFnProto = struct {
fn_token: Token,
name_token: ?Token,
params: ArrayList(&Node),
return_type: &Node,
return_type: ReturnType,
var_args_token: ?Token,
extern_token: ?Token,
inline_token: ?Token,
@ -111,6 +111,12 @@ pub const NodeFnProto = struct {
lib_name: ?&Node, // populated if this is an extern declaration
align_expr: ?&Node, // populated if align(A) is present
pub const ReturnType = union(enum) {
Explicit: &Node,
Infer,
InferErrorSet: &Node,
};
pub fn iterate(self: &NodeFnProto, index: usize) ?&Node {
var i = index;
@ -119,8 +125,18 @@ pub const NodeFnProto = struct {
i -= 1;
}
if (i < 1) return self.return_type;
i -= 1;
switch (self.return_type) {
// TODO allow this and next prong to share bodies since the types are the same
ReturnType.Explicit => |node| {
if (i < 1) return node;
i -= 1;
},
ReturnType.InferErrorSet => |node| {
if (i < 1) return node;
i -= 1;
},
ReturnType.Infer => {},
}
if (self.align_expr) |align_expr| {
if (i < 1) return align_expr;

79
std/zig/parser.zig
View File

@ -87,6 +87,7 @@ pub const Parser = struct {
ExpectToken: @TagType(Token.Id),
FnProto: &ast.NodeFnProto,
FnProtoAlign: &ast.NodeFnProto,
FnProtoReturnType: &ast.NodeFnProto,
ParamDecl: &ast.NodeFnProto,
ParamDeclComma,
FnDef: &ast.NodeFnProto,
@ -178,7 +179,7 @@ pub const Parser = struct {
stack.append(State.TopLevel) catch unreachable;
// TODO shouldn't need these casts
const fn_proto = try self.createAttachFnProto(arena, &root_node.decls, token,
ctx.extern_token, (?Token)(null), (?Token)(null), (?Token)(null));
ctx.extern_token, (?Token)(null), ctx.visib_token, (?Token)(null));
try stack.append(State { .FnDef = fn_proto });
try stack.append(State { .FnProto = fn_proto });
continue;
@ -466,11 +467,37 @@ pub const Parser = struct {
}
self.putBackToken(token);
stack.append(State {
.TypeExpr = DestPtr {.Field = &fn_proto.return_type},
.FnProtoReturnType = fn_proto,
}) catch unreachable;
continue;
},
State.FnProtoReturnType => |fn_proto| {
const token = self.getNextToken();
switch (token.id) {
Token.Id.Keyword_var => {
fn_proto.return_type = ast.NodeFnProto.ReturnType.Infer;
},
Token.Id.Bang => {
fn_proto.return_type = ast.NodeFnProto.ReturnType { .InferErrorSet = undefined };
stack.append(State {
.TypeExpr = DestPtr {.Field = &fn_proto.return_type.InferErrorSet},
}) catch unreachable;
},
else => {
self.putBackToken(token);
fn_proto.return_type = ast.NodeFnProto.ReturnType { .Explicit = undefined };
stack.append(State {
.TypeExpr = DestPtr {.Field = &fn_proto.return_type.Explicit},
}) catch unreachable;
},
}
if (token.id == Token.Id.Keyword_align) {
@panic("TODO fn proto align");
}
continue;
},
State.ParamDecl => |fn_proto| {
var token = self.getNextToken();
if (token.id == Token.Id.RParen) {
@ -977,19 +1004,23 @@ pub const Parser = struct {
},
ast.Node.Id.Block => {
const block = @fieldParentPtr(ast.NodeBlock, "base", base);
try stream.write("{");
try stack.append(RenderState { .Text = "}"});
try stack.append(RenderState.PrintIndent);
try stack.append(RenderState { .Indent = indent});
try stack.append(RenderState { .Text = "\n"});
var i = block.statements.len;
while (i != 0) {
i -= 1;
const statement_node = block.statements.items[i];
try stack.append(RenderState { .Statement = statement_node});
if (block.statements.len == 0) {
try stream.write("{}");
} else {
try stream.write("{");
try stack.append(RenderState { .Text = "}"});
try stack.append(RenderState.PrintIndent);
try stack.append(RenderState { .Indent = indent + indent_delta});
try stack.append(RenderState { .Text = "\n" });
try stack.append(RenderState { .Indent = indent});
try stack.append(RenderState { .Text = "\n"});
var i = block.statements.len;
while (i != 0) {
i -= 1;
const statement_node = block.statements.items[i];
try stack.append(RenderState { .Statement = statement_node});
try stack.append(RenderState.PrintIndent);
try stack.append(RenderState { .Indent = indent + indent_delta});
try stack.append(RenderState { .Text = "\n" });
}
}
},
ast.Node.Id.InfixOp => {
@ -1071,7 +1102,18 @@ pub const Parser = struct {
try stack.append(RenderState { .Expression = body_node});
try stack.append(RenderState { .Text = " "});
}
try stack.append(RenderState { .Expression = fn_proto.return_type});
switch (fn_proto.return_type) {
ast.NodeFnProto.ReturnType.Explicit => |node| {
try stack.append(RenderState { .Expression = node});
},
ast.NodeFnProto.ReturnType.Infer => {
try stream.print("var");
},
ast.NodeFnProto.ReturnType.InferErrorSet => |node| {
try stream.print("!");
try stack.append(RenderState { .Expression = node});
},
}
},
RenderState.Statement => |base| {
switch (base.id) {
@ -1169,6 +1211,13 @@ fn testCanonical(source: []const u8) !void {
}
test "zig fmt" {
try testCanonical(
\\pub fn main() !void {}
\\pub fn main() var {}
\\pub fn main() i32 {}
\\
);
try testCanonical(
\\const std = @import("std");
\\const std = @import();