tint: Add builtin type aliases (vec3f, etc)

Fixed: tint:1772
Change-Id: I4bed36ded91ca5288875ed6ea819ff4bbb432186
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/112340
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>

tools/src/tint/intrinsic/lexer/lexer.go

@@ -93,15 +93,26 @@ func (l *lexer) lex() error {
 			case l.match("/", tok.Divide):
 			case l.match(".", tok.Dot):
 			case l.match("->", tok.Arrow):
-			case l.match("fn", tok.Function):
-			case l.match("op", tok.Operator):
-			case l.match("enum", tok.Enum):
-			case l.match("type", tok.Type):
-			case l.match("init", tok.Initializer):
-			case l.match("conv", tok.Converter):
-			case l.match("match", tok.Match):
 			case unicode.IsLetter(l.peek(0)) || l.peek(0) == '_':
-				l.tok(l.count(alphaNumericOrUnderscore), tok.Identifier)
+				n := l.count(alphaNumericOrUnderscore)
+				switch string(l.runes[:n]) {
+				case "fn":
+					l.tok(n, tok.Function)
+				case "op":
+					l.tok(n, tok.Operator)
+				case "enum":
+					l.tok(n, tok.Enum)
+				case "type":
+					l.tok(n, tok.Type)
+				case "init":
+					l.tok(n, tok.Initializer)
+				case "conv":
+					l.tok(n, tok.Converter)
+				case "match":
+					l.tok(n, tok.Match)
+				default:
+					l.tok(n, tok.Identifier)
+				}
 			case unicode.IsNumber(l.peek(0)) || l.peek(0) == '-':
 				isFloat := false
 				isNegative := false

tools/src/tint/intrinsic/lexer/lexer_test.go

@@ -84,6 +84,9 @@ func TestLexTokens(t *testing.T) {
 		{"op", []tok.Token{{Kind: tok.Operator, Runes: []rune("op"), Source: tok.Source{
 			S: loc(1, 1, 0), E: loc(1, 3, 2),
 		}}}},
+		{"operation", []tok.Token{{Kind: tok.Identifier, Runes: []rune("operation"), Source: tok.Source{
+			S: loc(1, 1, 0), E: loc(1, 10, 9),
+		}}}},
 		{"type", []tok.Token{{Kind: tok.Type, Runes: []rune("type"), Source: tok.Source{
 			S: loc(1, 1, 0), E: loc(1, 5, 4),
 		}}}},