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package compiler
import (
"strings"
"testing"
)
func TestLexer(t *testing.T) {
tests := []struct {
caption string
src string
tokens []*token
err error
}{
{
caption: "lexer can recognize ordinaly characters",
src: "123abcいろは",
tokens: []*token{
newToken(tokenKindChar, '1'),
newToken(tokenKindChar, '2'),
newToken(tokenKindChar, '3'),
newToken(tokenKindChar, 'a'),
newToken(tokenKindChar, 'b'),
newToken(tokenKindChar, 'c'),
newToken(tokenKindChar, 'い'),
newToken(tokenKindChar, 'ろ'),
newToken(tokenKindChar, 'は'),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "lexer can recognize the special characters in default mode",
src: ".*+?|()[",
tokens: []*token{
newToken(tokenKindAnyChar, nullChar),
newToken(tokenKindRepeat, nullChar),
newToken(tokenKindRepeatOneOrMore, nullChar),
newToken(tokenKindOption, nullChar),
newToken(tokenKindAlt, nullChar),
newToken(tokenKindGroupOpen, nullChar),
newToken(tokenKindGroupClose, nullChar),
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "lexer can recognize the escape sequences in default mode",
src: "\\\\\\.\\*\\+\\?\\|\\(\\)\\[",
tokens: []*token{
newToken(tokenKindChar, '\\'),
newToken(tokenKindChar, '.'),
newToken(tokenKindChar, '*'),
newToken(tokenKindChar, '+'),
newToken(tokenKindChar, '?'),
newToken(tokenKindChar, '|'),
newToken(tokenKindChar, '('),
newToken(tokenKindChar, ')'),
newToken(tokenKindChar, '['),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "] is treated as an ordinary character in default mode",
src: "]",
tokens: []*token{
newToken(tokenKindChar, ']'),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "lexer can recognize the special characters in bracket expression mode",
src: "[a-z][^a-z]",
tokens: []*token{
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, 'a'),
newToken(tokenKindCharRange, nullChar),
newToken(tokenKindChar, 'z'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, 'a'),
newToken(tokenKindCharRange, nullChar),
newToken(tokenKindChar, 'z'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "lexer can recognize the escape sequences in bracket expression mode",
src: "[\\^a\\-z]",
tokens: []*token{
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, '^'),
newToken(tokenKindChar, 'a'),
newToken(tokenKindChar, '-'),
newToken(tokenKindChar, 'z'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "in a bracket expression, the special characters are also handled as normal characters",
src: "[\\\\.*+?|()[",
tokens: []*token{
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, '\\'),
newToken(tokenKindChar, '.'),
newToken(tokenKindChar, '*'),
newToken(tokenKindChar, '+'),
newToken(tokenKindChar, '?'),
newToken(tokenKindChar, '|'),
newToken(tokenKindChar, '('),
newToken(tokenKindChar, ')'),
newToken(tokenKindChar, '['),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "hyphen symbols that appear in bracket expressions are handled as the character range symbol or ordinary characters",
// [...-...][...-][-...][-]
// ~~~~~~~ ~ ~ ~
// ^ ^ ^ ^
// | | | `-- Ordinary Character (b)
// | | `-- Ordinary Character (b)
// | `-- Ordinary Character (b)
// `-- Character Range (a)
//
// a. *-* is handled as a character range expression.
// b. *-, -*, or - are handled as ordinary characters.
src: "[a-z][a-][-z][-][--][---][^a-z][^a-][^-z][^-][^--][^---]",
tokens: []*token{
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, 'a'),
newToken(tokenKindCharRange, nullChar),
newToken(tokenKindChar, 'z'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, 'a'),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindChar, 'z'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindCharRange, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, 'a'),
newToken(tokenKindCharRange, nullChar),
newToken(tokenKindChar, 'z'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, 'a'),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindChar, 'z'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindCharRange, nullChar),
newToken(tokenKindChar, '-'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "caret symbols that appear in bracket expressions are handled as the logical inverse symbol or ordinary characters",
// [^...^...][^]
// ~~ ~ ~~
// ^ ^ ^^
// | | |`-- Ordinary Character (c)
// | | `-- Bracket Expression
// | `-- Ordinary Character (b)
// `-- Inverse Bracket Expression (a)
//
// a. Bracket expressions that have a caret symbol at the beginning are handled as logical inverse expressions.
// b. caret symbols that appear as the second and the subsequent symbols are handled as ordinary symbols.
// c. When a bracket expression has just one symbol, a caret symbol at the beginning is handled as an ordinary character.
src: "[^^][^]",
tokens: []*token{
newToken(tokenKindInverseBExpOpen, nullChar),
newToken(tokenKindChar, '^'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindBExpOpen, nullChar),
newToken(tokenKindChar, '^'),
newToken(tokenKindBExpClose, nullChar),
newToken(tokenKindEOF, nullChar),
},
},
{
caption: "lexer raises an error when an invalid escape sequence appears",
src: "\\@",
err: synErrInvalidEscSeq,
},
{
caption: "lexer raises an error when the incomplete escape sequence (EOF following \\) appears",
src: "\\",
err: synErrIncompletedEscSeq,
},
{
caption: "lexer raises an error when an invalid escape sequence appears",
src: "[\\@",
tokens: []*token{
newToken(tokenKindBExpOpen, nullChar),
},
err: synErrInvalidEscSeq,
},
{
caption: "lexer raises an error when the incomplete escape sequence (EOF following \\) appears",
src: "[\\",
tokens: []*token{
newToken(tokenKindBExpOpen, nullChar),
},
err: synErrIncompletedEscSeq,
},
}
for _, tt := range tests {
t.Run(tt.caption, func(t *testing.T) {
lex := newLexer(strings.NewReader(tt.src))
var err error
var tok *token
i := 0
for {
tok, err = lex.next()
if err != nil {
break
}
if i >= len(tt.tokens) {
break
}
eTok := tt.tokens[i]
i++
testToken(t, tok, eTok)
if tok.kind == tokenKindEOF {
break
}
}
if err != tt.err {
t.Fatalf("unexpected error; want: %v, got: %v", tt.err, err)
}
if i < len(tt.tokens) {
t.Fatalf("expecte more tokens")
}
})
}
}
func testToken(t *testing.T, a, e *token) {
t.Helper()
if e.kind != a.kind || e.char != a.char {
t.Fatalf("unexpected token; want: %v, got: %v", e, a)
}
}
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