diff options
Diffstat (limited to 'compiler/parser.go')
| -rw-r--r-- | compiler/parser.go | 103 |
1 files changed, 68 insertions, 35 deletions
diff --git a/compiler/parser.go b/compiler/parser.go index d5c7b3d..623a174 100644 --- a/compiler/parser.go +++ b/compiler/parser.go @@ -2,7 +2,6 @@ package compiler import ( "bytes" - "errors" "fmt" "io" ) @@ -96,23 +95,23 @@ func newParser(id int, src io.Reader) *parser { } } -func (p *parser) parse() (astNode, error) { - return p.parseRegexp() -} - -func (p *parser) parseRegexp() (ast astNode, retErr error) { +func (p *parser) parse() (ast astNode, retErr error) { defer func() { err := recover() if err != nil { - retErr = err.(error) - var synErr SyntaxError - if !errors.Is(retErr, &synErr) { - panic(err) + var ok bool + retErr, ok = err.(error) + if !ok { + retErr = fmt.Errorf("Error: %v", err) } return } }() + return p.parseRegexp() +} + +func (p *parser) parseRegexp() (astNode, error) { alt := p.parseAlt() p.expect(tokenKindEOF) return newConcatNode(alt, newEndMarkerNode(p.id)), nil @@ -120,11 +119,17 @@ func (p *parser) parseRegexp() (ast astNode, retErr error) { func (p *parser) parseAlt() astNode { left := p.parseConcat() + if left == nil { + raiseSyntaxError("alternation expression must have operands") + } for { if !p.consume(tokenKindAlt) { break } right := p.parseConcat() + if right == nil { + raiseSyntaxError("alternation expression must have operands") + } left = newAltNode(left, right) } return left @@ -144,6 +149,9 @@ func (p *parser) parseConcat() astNode { func (p *parser) parseRepeat() astNode { group := p.parseGroup() + if group == nil { + return nil + } if p.consume(tokenKindRepeat) { return newRepeatNode(group) } @@ -159,7 +167,11 @@ func (p *parser) parseRepeat() astNode { func (p *parser) parseGroup() astNode { if p.consume(tokenKindGroupOpen) { defer p.expect(tokenKindGroupClose) - return p.parseAlt() + alt := p.parseAlt() + if alt == nil { + raiseSyntaxError("grouping expression must include at least one character") + } + return alt } return p.parseSingleChar() } @@ -169,7 +181,6 @@ func (p *parser) parseSingleChar() astNode { return genAnyCharAST() } if p.consume(tokenKindBExpOpen) { - defer p.expect(tokenKindBExpClose) left := p.parseBExpElem() if left == nil { raiseSyntaxError("bracket expression must include at least one character") @@ -181,10 +192,10 @@ func (p *parser) parseSingleChar() astNode { } left = newAltNode(left, right) } + p.expect(tokenKindBExpClose) return left } if p.consume(tokenKindInverseBExpOpen) { - defer p.expect(tokenKindBExpClose) elem := p.parseBExpElem() if elem == nil { raiseSyntaxError("bracket expression must include at least one character") @@ -203,6 +214,7 @@ func (p *parser) parseSingleChar() astNode { panic(fmt.Errorf("a pattern that isn't matching any symbols")) } } + p.expect(tokenKindBExpClose) return inverse } return p.parseNormalChar() @@ -210,6 +222,9 @@ func (p *parser) parseSingleChar() astNode { func (p *parser) parseBExpElem() astNode { left := p.parseNormalChar() + if left == nil { + return nil + } if !p.consume(tokenKindCharRange) { return left } @@ -258,6 +273,14 @@ func exclude(symbol, base astNode) astNode { exclude(symbol, left), exclude(symbol, right), ) + case *concatNode: + baseSeq := genByteRangeSeq(base) + symSeq := genByteRangeSeq(symbol) + excluded := excludeByteRangeSequence(symSeq, baseSeq) + if len(excluded) <= 0 { + return nil + } + return convertByteRangeSeqsToAST(excluded) case *symbolNode: baseSeq := genByteRangeSeq(base) symSeq := genByteRangeSeq(symbol) @@ -448,6 +471,38 @@ func isValidOrder(from, to []byte) bool { return true } +type byteBoundsEntry struct { + min byte + max byte +} + +var ( + bounds1 = [][]byteBoundsEntry{ + nil, + {{min: 0x00, max: 0x7f}}, + } + + bounds2 = [][]byteBoundsEntry{ + nil, + {{min: 0xc2, max: 0xdf}, {min: 0x80, max: 0xbf}}, + } + + bounds3 = [][]byteBoundsEntry{ + nil, + {{min: 0xe0, max: 0xe0}, {min: 0xa0, max: 0xbf}, {min: 0x80, max: 0xbf}}, + {{min: 0xe1, max: 0xec}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, + {{min: 0xed, max: 0xed}, {min: 0x80, max: 0x9f}, {min: 0x80, max: 0xbf}}, + {{min: 0xee, max: 0xef}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, + } + + bounds4 = [][]byteBoundsEntry{ + nil, + {{min: 0xf0, max: 0xf0}, {min: 0x90, max: 0xbf}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, + {{min: 0xf1, max: 0xf3}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, + {{min: 0xf4, max: 0xf4}, {min: 0x80, max: 0x8f}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, + } +) + func gen1ByteCharRangeAST(from, to []byte) astNode { return newRangeSymbolNode(from[0], to[0]) } @@ -481,28 +536,6 @@ func gen2ByteCharRangeAST(from, to []byte) astNode { } } -type byteBoundsEntry struct { - min byte - max byte -} - -var ( - bounds3 = [][]byteBoundsEntry{ - nil, - {{min: 0xe0, max: 0xe0}, {min: 0xa0, max: 0xbf}, {min: 0x80, max: 0xbf}}, - {{min: 0xe1, max: 0xec}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, - {{min: 0xed, max: 0xed}, {min: 0x80, max: 0x9f}, {min: 0x80, max: 0xbf}}, - {{min: 0xee, max: 0xef}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, - } - - bounds4 = [][]byteBoundsEntry{ - nil, - {{min: 0xf0, max: 0xf0}, {min: 0x90, max: 0xbf}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, - {{min: 0xf1, max: 0xf3}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, - {{min: 0xf4, max: 0xf4}, {min: 0x80, max: 0x8f}, {min: 0x80, max: 0xbf}, {min: 0x80, max: 0xbf}}, - } -) - func get3ByteCharRangeNum(seq []byte) int { head := seq[0] switch { |