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std.zig.fmtId: conditionally escape primitives/_

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This is a breaking change.

This updates `std.zig.fmtId` to support conditionally escaping
primitives and the reserved `_` identifier via format specifiers:

- `{}`: escape invalid identifiers, identifiers that shadow primitives
  and the reserved `_` identifier.
- `{p}`: same as `{}`, but don't escape identifiers that
  shadow primitives.
- `{_}`: same as `{}`, but don't escape the reserved `_` identifier.
- `{p_}` or `{_p}`: only escape invalid identifiers.

(The idea is that `p`/`_` mean "allow primitives/underscores".)

Any other format specifiers will result in compile errors.

Additionally, `isValidId` now considers `_` a valid identifier. If this
distinction is important, consider combining existing uses of this
function with the new `isUnderscore` function.
This commit is contained in:
Carl Åstholm 2024-02-13 18:30:22 +01:00
parent 129de47a71
commit d8e7eda5f4
1 changed files with 86 additions and 11 deletions
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97
lib/std/zig.zig
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@ -10,6 +10,7 @@ pub const Tokenizer = tokenizer.Tokenizer;
pub const string_literal = @import("zig/string_literal.zig");
pub const number_literal = @import("zig/number_literal.zig");
pub const primitives = @import("zig/primitives.zig");
pub const isPrimitive = primitives.isPrimitive;
pub const Ast = @import("zig/Ast.zig");
pub const AstGen = @import("zig/AstGen.zig");
pub const Zir = @import("zig/Zir.zig");
@ -728,20 +729,87 @@ const tokenizer = @import("zig/tokenizer.zig");
const assert = std.debug.assert;
const Allocator = std.mem.Allocator;
/// Return a Formatter for a Zig identifier
/// Return a Formatter for a Zig identifier, escaping it with `@""` syntax if needed.
///
/// - An empty `{}` format specifier escapes invalid identifiers, identifiers that shadow primitives
/// and the reserved `_` identifier.
/// - Add `p` to the specifier to render identifiers that shadow primitives unescaped.
/// - Add `_` to the specifier to render the reserved `_` identifier unescaped.
/// - `p` and `_` can be combined, e.g. `{p_}`.
///
pub fn fmtId(bytes: []const u8) std.fmt.Formatter(formatId) {
return .{ .data = bytes };
}
/// Print the string as a Zig identifier escaping it with @"" syntax if needed.
test fmtId {
const expectFmt = std.testing.expectFmt;
try expectFmt("@\"while\"", "{}", .{fmtId("while")});
try expectFmt("@\"while\"", "{p}", .{fmtId("while")});
try expectFmt("@\"while\"", "{_}", .{fmtId("while")});
try expectFmt("@\"while\"", "{p_}", .{fmtId("while")});
try expectFmt("@\"while\"", "{_p}", .{fmtId("while")});
try expectFmt("hello", "{}", .{fmtId("hello")});
try expectFmt("hello", "{p}", .{fmtId("hello")});
try expectFmt("hello", "{_}", .{fmtId("hello")});
try expectFmt("hello", "{p_}", .{fmtId("hello")});
try expectFmt("hello", "{_p}", .{fmtId("hello")});
try expectFmt("@\"type\"", "{}", .{fmtId("type")});
try expectFmt("type", "{p}", .{fmtId("type")});
try expectFmt("@\"type\"", "{_}", .{fmtId("type")});
try expectFmt("type", "{p_}", .{fmtId("type")});
try expectFmt("type", "{_p}", .{fmtId("type")});
try expectFmt("@\"_\"", "{}", .{fmtId("_")});
try expectFmt("@\"_\"", "{p}", .{fmtId("_")});
try expectFmt("_", "{_}", .{fmtId("_")});
try expectFmt("_", "{p_}", .{fmtId("_")});
try expectFmt("_", "{_p}", .{fmtId("_")});
try expectFmt("@\"i123\"", "{}", .{fmtId("i123")});
try expectFmt("i123", "{p}", .{fmtId("i123")});
try expectFmt("@\"4four\"", "{}", .{fmtId("4four")});
try expectFmt("_underscore", "{}", .{fmtId("_underscore")});
try expectFmt("@\"11\\\"23\"", "{}", .{fmtId("11\"23")});
try expectFmt("@\"11\\x0f23\"", "{}", .{fmtId("11\x0F23")});
// These are technically not currently legal in Zig.
try expectFmt("@\"\"", "{}", .{fmtId("")});
try expectFmt("@\"\\x00\"", "{}", .{fmtId("\x00")});
}
/// Print the string as a Zig identifier, escaping it with `@""` syntax if needed.
fn formatId(
bytes: []const u8,
comptime unused_format_string: []const u8,
comptime fmt: []const u8,
options: std.fmt.FormatOptions,
writer: anytype,
) !void {
_ = unused_format_string;
if (isValidId(bytes)) {
const allow_primitive, const allow_underscore = comptime parse_fmt: {
var allow_primitive = false;
var allow_underscore = false;
for (fmt) |char| {
switch (char) {
'p' => if (!allow_primitive) {
allow_primitive = true;
continue;
},
'_' => if (!allow_underscore) {
allow_underscore = true;
continue;
},
else => {},
}
@compileError("expected {}, {p}, {_}, {p_} or {_p}, found {" ++ fmt ++ "}");
}
break :parse_fmt .{ allow_primitive, allow_underscore };
};
if (isValidId(bytes) and
(allow_primitive or !std.zig.isPrimitive(bytes)) and
(allow_underscore or !isUnderscore(bytes)))
{
return writer.writeAll(bytes);
}
try writer.writeAll("@\"");
@ -757,12 +825,8 @@ pub fn fmtEscapes(bytes: []const u8) std.fmt.Formatter(stringEscape) {
return .{ .data = bytes };
}
test "escape invalid identifiers" {
test fmtEscapes {
const expectFmt = std.testing.expectFmt;
try expectFmt("@\"while\"", "{}", .{fmtId("while")});
try expectFmt("hello", "{}", .{fmtId("hello")});
try expectFmt("@\"11\\\"23\"", "{}", .{fmtId("11\"23")});
try expectFmt("@\"11\\x0f23\"", "{}", .{fmtId("11\x0F23")});
try expectFmt("\\x0f", "{}", .{fmtEscapes("\x0f")});
try expectFmt(
\\" \\ hi \x07 \x11 " derp \'"
@ -816,7 +880,6 @@ pub fn stringEscape(
pub fn isValidId(bytes: []const u8) bool {
if (bytes.len == 0) return false;
if (std.mem.eql(u8, bytes, "_")) return false;
for (bytes, 0..) |c, i| {
switch (c) {
'_', 'a'...'z', 'A'...'Z' => {},
@ -836,6 +899,18 @@ test isValidId {
try std.testing.expect(isValidId("i386"));
}
pub fn isUnderscore(bytes: []const u8) bool {
return bytes.len == 1 and bytes[0] == '_';
}
test isUnderscore {
try std.testing.expect(isUnderscore("_"));
try std.testing.expect(!isUnderscore("__"));
try std.testing.expect(!isUnderscore("_foo"));
try std.testing.expect(isUnderscore("\x5f"));
try std.testing.expect(!isUnderscore("\\x5f"));
}
pub fn readSourceFileToEndAlloc(
allocator: Allocator,
input: std.fs.File,