amery
2b9996da7c
only logging position, errors and non-whitespace elements Signed-off-by: Alejandro Mery <amery@jpi.io>
72 lines
1.2 KiB
Go
72 lines
1.2 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.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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log.Printf("%s: %s: %s", p.pos, "error", err)
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return nil, 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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case IsSpace(r):
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// whitespace
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p.lexWhitespace()
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default:
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// token
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p.src.UnreadRune()
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return p.lexToken, nil
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}
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}
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}
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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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func (p *Parser) lexWhitespace() {
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p.src.Discard()
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p.pos.Step()
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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 {
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case r1 == '\r' && r2 == '\n':
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// CR LN
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case r1 == '\r' && err == nil:
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// CR
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p.src.UnreadRune()
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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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}
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p.src.Discard()
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p.pos.StepLine()
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}
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