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