You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
58 lines
1.2 KiB
58 lines
1.2 KiB
package parser
|
|
|
|
import (
|
|
"io"
|
|
|
|
"github.com/brettlangdon/gython/ast"
|
|
"github.com/brettlangdon/gython/errorcode"
|
|
"github.com/brettlangdon/gython/scanner"
|
|
"github.com/brettlangdon/gython/token"
|
|
)
|
|
|
|
type Parser struct {
|
|
tokenizer *scanner.Scanner
|
|
|
|
tokenBuffer []*token.Token
|
|
}
|
|
|
|
func (parser *Parser) nextToken() *token.Token {
|
|
if len(parser.tokenBuffer) > 0 {
|
|
last := len(parser.tokenBuffer) - 1
|
|
next := parser.tokenBuffer[last]
|
|
parser.tokenBuffer = parser.tokenBuffer[:last]
|
|
return next
|
|
}
|
|
|
|
return parser.tokenizer.NextToken()
|
|
}
|
|
|
|
func (parser *Parser) unreadToken(tok *token.Token) {
|
|
parser.tokenBuffer = append(parser.tokenBuffer, tok)
|
|
}
|
|
|
|
func (parser *Parser) parseFileInput() *ast.FileInput {
|
|
root := ast.NewFileInput()
|
|
for parser.tokenizer.State() == errorcode.E_OK {
|
|
next := parser.nextToken()
|
|
if next.ID == token.NEWLINE {
|
|
root.AppendToken(next)
|
|
} else if next.ID == token.ENDMARKER {
|
|
break
|
|
} else {
|
|
parser.unreadToken(next)
|
|
// TODO: parser.parseStatement()
|
|
break
|
|
}
|
|
}
|
|
|
|
return root
|
|
}
|
|
|
|
func ParseReader(r io.Reader) *ast.FileInput {
|
|
parser := &Parser{
|
|
tokenizer: scanner.NewScanner(r),
|
|
tokenBuffer: make([]*token.Token, 0),
|
|
}
|
|
|
|
return parser.parseFileInput()
|
|
}
|