100 lines
1.7 KiB
Go
100 lines
1.7 KiB
Go
package parser
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import (
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"log"
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"asciigoat.org/core/lexer"
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)
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// Run parses the source
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func (p *Parser) Run() error {
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p.setDefaults()
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p.pos.Reset()
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return lexer.Run(p.lexStart)
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}
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func (p *Parser) lexStart() (lexer.StateFn, error) {
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for {
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r, _, err := p.src.ReadRune()
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switch {
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case err != nil:
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// read error
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return p.emitError("", err)
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case IsNewLine(r):
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// new line
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p.lexNewLine(r)
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p.src.Discard()
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p.pos.StepLine()
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case IsSpace(r):
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// whitespace
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p.src.Discard()
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p.pos.Step()
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case IsCommentStart(r):
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// switch to comment lexer
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p.src.UnreadRune()
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return p.lexComment, nil
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case IsSectionStart(r):
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// section
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p.src.Discard()
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p.pos.Step()
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return p.lexSectionStart, nil
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default:
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// entry
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p.src.UnreadRune()
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return p.lexEntryStart, nil
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}
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}
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}
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func (p *Parser) lexNewLine(r1 rune) {
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// r1 is warrantied to be either \n or \r
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r2, _, err := p.src.ReadRune()
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switch r1 {
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case '\r':
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switch {
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case r2 == '\n':
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// CR LN
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case err == nil:
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// CR
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p.src.UnreadRune()
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default:
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// CR EOF
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}
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case '\n':
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switch {
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case r2 == '\r':
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// LN CR
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case err == nil:
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// LN
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p.src.UnreadRune()
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default:
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// LN EOF
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}
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default:
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panic("unreachable")
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}
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}
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func (p *Parser) lexComment() (lexer.StateFn, error) {
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// until the end of the line
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p.src.AcceptAll(IsNotNewLine)
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err := p.OnComment(p.pos, p.src.Emit())
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return p.lexStart, err
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}
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func (*Parser) lexSectionStart() (lexer.StateFn, error) { return nil, nil }
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func (*Parser) lexEntryStart() (lexer.StateFn, error) { return nil, nil }
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func (p *Parser) lexToken() (lexer.StateFn, error) {
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p.src.AcceptAll(IsNotSpace)
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s := p.src.Emit()
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log.Printf("%s: %s: %q", p.pos, "token", s)
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p.pos.StepN(len(s))
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return p.lexStart, nil
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}
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