alandonovan | 34a3319 | 2019-02-22 14:25:09 -0500 | [diff] [blame] | 1 | package syntax_test |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "fmt" |
| 6 | "log" |
| 7 | "reflect" |
| 8 | "strings" |
| 9 | "testing" |
| 10 | |
| 11 | "go.starlark.net/syntax" |
| 12 | ) |
| 13 | |
| 14 | func TestWalk(t *testing.T) { |
| 15 | const src = ` |
| 16 | for x in y: |
| 17 | if x: |
| 18 | pass |
| 19 | else: |
| 20 | f([2*x for x in "abc"]) |
| 21 | ` |
| 22 | // TODO(adonovan): test that it finds all syntax.Nodes |
| 23 | // (compare against a reflect-based implementation). |
| 24 | // TODO(adonovan): test that the result of f is used to prune |
| 25 | // the descent. |
| 26 | f, err := syntax.Parse("hello.go", src, 0) |
| 27 | if err != nil { |
| 28 | t.Fatal(err) |
| 29 | } |
| 30 | |
| 31 | var buf bytes.Buffer |
| 32 | var depth int |
| 33 | syntax.Walk(f, func(n syntax.Node) bool { |
| 34 | if n == nil { |
| 35 | depth-- |
| 36 | return true |
| 37 | } |
| 38 | fmt.Fprintf(&buf, "%s%s\n", |
| 39 | strings.Repeat(" ", depth), |
| 40 | strings.TrimPrefix(reflect.TypeOf(n).String(), "*syntax.")) |
| 41 | depth++ |
| 42 | return true |
| 43 | }) |
| 44 | got := buf.String() |
| 45 | want := ` |
| 46 | File |
| 47 | ForStmt |
| 48 | Ident |
| 49 | Ident |
| 50 | IfStmt |
| 51 | Ident |
| 52 | BranchStmt |
| 53 | ExprStmt |
| 54 | CallExpr |
| 55 | Ident |
| 56 | Comprehension |
| 57 | BinaryExpr |
| 58 | Literal |
| 59 | Ident |
| 60 | ForClause |
| 61 | Ident |
| 62 | Literal` |
| 63 | got = strings.TrimSpace(got) |
| 64 | want = strings.TrimSpace(want) |
| 65 | if got != want { |
| 66 | t.Errorf("got %s, want %s", got, want) |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | // ExampleWalk demonstrates the use of Walk to |
| 71 | // enumerate the identifiers in a Starlark source file |
| 72 | // containing a nonsense program with varied grammar. |
| 73 | func ExampleWalk() { |
| 74 | const src = ` |
| 75 | load("library", "a") |
| 76 | |
| 77 | def b(c, *, d=e): |
| 78 | f += {g: h} |
| 79 | i = -(j) |
| 80 | return k.l[m + n] |
| 81 | |
| 82 | for o in [p for q, r in s if t]: |
| 83 | u(lambda: v, w[x:y:z]) |
| 84 | ` |
| 85 | f, err := syntax.Parse("hello.star", src, 0) |
| 86 | if err != nil { |
| 87 | log.Fatal(err) |
| 88 | } |
| 89 | |
| 90 | var idents []string |
| 91 | syntax.Walk(f, func(n syntax.Node) bool { |
| 92 | if id, ok := n.(*syntax.Ident); ok { |
| 93 | idents = append(idents, id.Name) |
| 94 | } |
| 95 | return true |
| 96 | }) |
| 97 | fmt.Println(strings.Join(idents, " ")) |
| 98 | |
| 99 | // The identifer 'a' appears in both LoadStmt.From[0] and LoadStmt.To[0]. |
| 100 | |
| 101 | // Output: |
| 102 | // 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 |
| 103 | } |