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104 lines
1.9 KiB
104 lines
1.9 KiB
4 months ago
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package syntax_test
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import (
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"bytes"
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"fmt"
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"log"
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"reflect"
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"strings"
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"testing"
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"go.starlark.net/syntax"
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)
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func TestWalk(t *testing.T) {
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const src = `
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for x in y:
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if x:
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pass
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else:
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f([2*x for x in "abc"])
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`
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// TODO(adonovan): test that it finds all syntax.Nodes
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// (compare against a reflect-based implementation).
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// TODO(adonovan): test that the result of f is used to prune
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// the descent.
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f, err := syntax.Parse("hello.go", src, 0)
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if err != nil {
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t.Fatal(err)
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}
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var buf bytes.Buffer
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var depth int
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syntax.Walk(f, func(n syntax.Node) bool {
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if n == nil {
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depth--
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return true
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}
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fmt.Fprintf(&buf, "%s%s\n",
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strings.Repeat(" ", depth),
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strings.TrimPrefix(reflect.TypeOf(n).String(), "*syntax."))
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depth++
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return true
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})
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got := buf.String()
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want := `
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File
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ForStmt
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Ident
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Ident
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IfStmt
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Ident
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BranchStmt
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ExprStmt
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CallExpr
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Ident
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Comprehension
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BinaryExpr
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Literal
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Ident
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ForClause
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Ident
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Literal`
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got = strings.TrimSpace(got)
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want = strings.TrimSpace(want)
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if got != want {
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t.Errorf("got %s, want %s", got, want)
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}
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}
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// ExampleWalk demonstrates the use of Walk to
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// enumerate the identifiers in a Starlark source file
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// containing a nonsense program with varied grammar.
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func ExampleWalk() {
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const src = `
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load("library", "a")
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def b(c, *, d=e):
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f += {g: h}
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i = -(j)
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return k.l[m + n]
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for o in [p for q, r in s if t]:
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u(lambda: v, w[x:y:z])
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`
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f, err := syntax.Parse("hello.star", src, 0)
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if err != nil {
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log.Fatal(err)
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}
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var idents []string
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syntax.Walk(f, func(n syntax.Node) bool {
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if id, ok := n.(*syntax.Ident); ok {
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idents = append(idents, id.Name)
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}
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return true
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})
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fmt.Println(strings.Join(idents, " "))
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// The identifer 'a' appears in both LoadStmt.From[0] and LoadStmt.To[0].
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// Output:
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// a a b c d e f g h i j k l m n o p q r s t u v w x y z
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}
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