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package common
import (
"fmt"
"text/scanner"
"github.com/vektah/gqlgen/neelance/errors"
)
type syntaxError string
type Lexer struct {
sc *scanner.Scanner
next rune
descComment string
}
type Ident struct {
Name string
Loc errors.Location
}
func New(sc *scanner.Scanner) *Lexer {
l := &Lexer{sc: sc}
l.Consume()
return l
}
func (l *Lexer) CatchSyntaxError(f func()) (errRes *errors.QueryError) {
defer func() {
if err := recover(); err != nil {
if err, ok := err.(syntaxError); ok {
errRes = errors.Errorf("syntax error: %s", err)
errRes.Locations = []errors.Location{l.Location()}
return
}
panic(err)
}
}()
f()
return
}
func (l *Lexer) Peek() rune {
return l.next
}
func (l *Lexer) Consume() {
l.descComment = ""
for {
l.next = l.sc.Scan()
if l.next == ',' {
continue
}
if l.next == '#' {
if l.sc.Peek() == ' ' {
l.sc.Next()
}
if l.descComment != "" {
l.descComment += "\n"
}
for {
next := l.sc.Next()
if next == '\n' || next == scanner.EOF {
break
}
l.descComment += string(next)
}
continue
}
break
}
}
func (l *Lexer) ConsumeIdent() string {
name := l.sc.TokenText()
l.ConsumeToken(scanner.Ident)
return name
}
func (l *Lexer) ConsumeIdentWithLoc() Ident {
loc := l.Location()
name := l.sc.TokenText()
l.ConsumeToken(scanner.Ident)
return Ident{name, loc}
}
func (l *Lexer) ConsumeKeyword(keyword string) {
if l.next != scanner.Ident || l.sc.TokenText() != keyword {
l.SyntaxError(fmt.Sprintf("unexpected %q, expecting %q", l.sc.TokenText(), keyword))
}
l.Consume()
}
func (l *Lexer) ConsumeLiteral() *BasicLit {
lit := &BasicLit{Type: l.next, Text: l.sc.TokenText()}
l.Consume()
return lit
}
func (l *Lexer) ConsumeToken(expected rune) {
if l.next != expected {
l.SyntaxError(fmt.Sprintf("unexpected %q, expecting %s", l.sc.TokenText(), scanner.TokenString(expected)))
}
l.Consume()
}
func (l *Lexer) DescComment() string {
return l.descComment
}
func (l *Lexer) SyntaxError(message string) {
panic(syntaxError(message))
}
func (l *Lexer) Location() errors.Location {
return errors.Location{
Line: l.sc.Line,
Column: l.sc.Column,
}
}
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