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https://github.com/robertkrimen/otto
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50ed21f88e
* (#257) Change Walk/Visit to follow an explicit Enter/Exit pattern * (#257) Convert walk example into test. * (#257) restore walk/visitor example * (#257) Fix godoc comment in the Visitor interface ... typo referred to `End` method instead of `Exit`
53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
package ast_test
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import (
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"fmt"
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"log"
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"github.com/robertkrimen/otto/ast"
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"github.com/robertkrimen/otto/file"
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"github.com/robertkrimen/otto/parser"
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)
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type walkExample struct {
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source string
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shift file.Idx
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}
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func (w *walkExample) Enter(n ast.Node) ast.Visitor {
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if id, ok := n.(*ast.Identifier); ok && id != nil {
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idx := n.Idx0() + w.shift - 1
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s := w.source[:idx] + "new_" + w.source[idx:]
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w.source = s
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w.shift += 4
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}
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if v, ok := n.(*ast.VariableExpression); ok && v != nil {
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idx := n.Idx0() + w.shift - 1
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s := w.source[:idx] + "varnew_" + w.source[idx:]
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w.source = s
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w.shift += 7
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}
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return w
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}
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func (w *walkExample) Exit(n ast.Node) {
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// AST node n has had all its children walked. Pop it out of your
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// stack, or do whatever processing you need to do, if any.
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}
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func ExampleVisitor_codeRewrite() {
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source := `var b = function() {test(); try {} catch(e) {} var test = "test(); var test = 1"} // test`
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program, err := parser.ParseFile(nil, "", source, 0)
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if err != nil {
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log.Fatal(err)
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}
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w := &walkExample{source: source}
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ast.Walk(w, program)
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fmt.Println(w.source)
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// Output: var varnew_b = function() {new_test(); try {} catch(new_e) {} var varnew_test = "test(); var test = 1"} // test
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}
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