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main.go
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main.go
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//Copyright 2013 Vastech SA (PTY) LTD
//
//Licensed under the Apache License, Version 2.0 (the "License");
//you may not use this file except in compliance with the License.
//You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
//Unless required by applicable law or agreed to in writing, software
//distributed under the License is distributed on an "AS IS" BASIS,
//WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//See the License for the specific language governing permissions and
//limitations under the License.
//A parser for the DOT grammar.
package parser
import (
"fmt"
"github.com/awalterschulze/gographviz/ast"
"github.com/awalterschulze/gographviz/scanner"
"github.com/awalterschulze/gographviz/token"
"io"
"io/ioutil"
"os"
)
//Parses a DOT string and outputs the
//abstract syntax tree representing the graph.
func ParseString(dotString string) (*ast.Graph, error) {
return ParseBytes([]byte(dotString))
}
//Parses the bytes representing a DOT string
//and outputs the abstract syntax tree representing the graph.
func ParseBytes(dotBytes []byte) (*ast.Graph, error) {
lex := &scanner.Scanner{}
lex.Init(dotBytes, token.DOTTokens)
parser := NewParser(ActionTable, GotoTable, ProductionsTable, token.DOTTokens)
st, err := parser.Parse(lex)
if err != nil {
return nil, err
}
g, ok := st.(*ast.Graph)
if !ok {
panic(fmt.Sprintf("Parser did not return an *ast.Graph, but rather a %T", st))
}
return g, err
}
//Parses a reader which contains a DOT string
//and outputs the abstract syntax tree representing the graph.
func Parse(r io.Reader) (*ast.Graph, error) {
bytes, err := ioutil.ReadAll(r)
if err != nil {
return nil, err
}
return ParseBytes(bytes)
}
//Parses a file which contains a DOT string
//and outputs the abstract syntax tree representing the graph.
func ParseFile(filename string) (*ast.Graph, error) {
f, err := os.Open(filename)
if err != nil {
return nil, err
}
return Parse(f)
}