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parse.zig: simplify parseSwitchProng and make one item cases with trailing commas produce .switch_case_one nodes

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Matthew Borkowski 2021-06-11 17:59:41 -04:00 committed by Veikka Tuominen
parent 51beb71480
commit 3692fb039d
1 changed files with 31 additions and 36 deletions
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67
lib/std/zig/parse.zig
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@ -2976,53 +2976,48 @@ const Parser = struct {
/// <- SwitchItem (COMMA SwitchItem)* COMMA?
/// / KEYWORD_else
fn parseSwitchProng(p: *Parser) !Node.Index {
if (p.eatToken(.keyword_else)) |_| {
const arrow_token = try p.expectToken(.equal_angle_bracket_right);
_ = try p.parsePtrPayload();
return p.addNode(.{
const scratch_top = p.scratch.items.len;
defer p.scratch.shrinkRetainingCapacity(scratch_top);
if (p.eatToken(.keyword_else) == null) {
while (true) {
const item = try p.parseSwitchItem();
if (item == 0) break;
try p.scratch.append(p.gpa, item);
if (p.eatToken(.comma) == null) break;
}
if (scratch_top == p.scratch.items.len) return null_node;
}
const arrow_token = try p.expectToken(.equal_angle_bracket_right);
_ = try p.parsePtrPayload();
const items = p.scratch.items[scratch_top..];
switch(items.len) {
0 => return p.addNode(.{
.tag = .switch_case_one,
.main_token = arrow_token,
.data = .{
.lhs = 0,
.rhs = try p.expectAssignExpr(),
},
});
}
const first_item = try p.parseSwitchItem();
if (first_item == 0) return null_node;
if (p.eatToken(.equal_angle_bracket_right)) |arrow_token| {
_ = try p.parsePtrPayload();
return p.addNode(.{
}
}),
1 => return p.addNode(.{
.tag = .switch_case_one,
.main_token = arrow_token,
.data = .{
.lhs = first_item,
.lhs = items[0],
.rhs = try p.expectAssignExpr(),
}
}),
else => return p.addNode(.{
.tag = .switch_case,
.main_token = arrow_token,
.data = .{
.lhs = try p.addExtra(try p.listToSpan(items)),
.rhs = try p.expectAssignExpr(),
},
});
}),
}
const scratch_top = p.scratch.items.len;
defer p.scratch.shrinkRetainingCapacity(scratch_top);
try p.scratch.append(p.gpa, first_item);
while (p.eatToken(.comma)) |_| {
const next_item = try p.parseSwitchItem();
if (next_item == 0) break;
try p.scratch.append(p.gpa, next_item);
}
const span = try p.listToSpan(p.scratch.items[scratch_top..]);
const arrow_token = try p.expectToken(.equal_angle_bracket_right);
_ = try p.parsePtrPayload();
return p.addNode(.{
.tag = .switch_case,
.main_token = arrow_token,
.data = .{
.lhs = try p.addExtra(span),
.rhs = try p.expectAssignExpr(),
},
});
}
/// SwitchItem <- Expr (DOT3 Expr)?