pysig.Parse; py/pandas

chore/llpyg/pysig/parse.go

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * 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.
+ */
+
+package pysig
+
+import (
+	"strings"
+)
+
+type Arg struct {
+	Name   string
+	Type   string
+	DefVal string
+}
+
+// Parse parses a Python function signature.
+func Parse(sig string) (args []*Arg) {
+	sig = strings.TrimPrefix(sig, "(")
+	for {
+		pos := strings.IndexAny(sig, ",:=)")
+		if pos <= 0 {
+			return
+		}
+		arg := &Arg{Name: strings.TrimSpace(sig[:pos])}
+		args = append(args, arg)
+		c := sig[pos]
+		sig = sig[pos+1:]
+		switch c {
+		case ',':
+			continue
+		case ':':
+			arg.Type, sig = parseType(sig)
+			if strings.HasPrefix(sig, "=") {
+				arg.DefVal, sig = parseDefVal(sig[1:])
+			}
+		case '=':
+			arg.DefVal, sig = parseDefVal(sig)
+		case ')':
+			return
+		}
+		sig = strings.TrimPrefix(sig, ",")
+	}
+}
+
+const (
+	allSpecials = "([<'\""
+)
+
+var pairStops = map[byte]string{
+	'(':  ")" + allSpecials,
+	'[':  "]" + allSpecials,
+	'<':  ">" + allSpecials,
+	'\'': "'" + allSpecials,
+	'"':  "\"",
+}
+
+func parseText(sig string, stops string) (left string) {
+	for {
+		pos := strings.IndexAny(sig, stops)
+		if pos < 0 {
+			return sig
+		}
+		if c := sig[pos]; c != stops[0] {
+			if pstop, ok := pairStops[c]; ok {
+				sig = strings.TrimPrefix(parseText(sig[pos+1:], pstop), pstop[:1])
+				continue
+			}
+		}
+		return sig[pos:]
+	}
+}
+
+// stops: "=,)"
+func parseType(sig string) (string, string) {
+	left := parseText(sig, "=,)"+allSpecials)
+	return resultOf(sig, left), left
+}
+
+// stops: ",)"
+func parseDefVal(sig string) (string, string) {
+	left := parseText(sig, ",)"+allSpecials)
+	return resultOf(sig, left), left
+}
+
+func resultOf(sig, left string) string {
+	return strings.TrimSpace(sig[:len(sig)-len(left)])
+}

chore/llpyg/pysig/parse_test.go

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * 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.
+ */
+
+package pysig
+
+import "testing"
+
+func TestParse(t *testing.T) {
+	type testCase struct {
+		sig  string
+		args []*Arg
+	}
+	cases := []testCase{
+		{"(start=None, *, unit: 'str | None' = None) -> 'TimedeltaIndex'", []*Arg{
+			{Name: "start", DefVal: "None"},
+			{Name: "*"},
+			{Name: "unit", Type: "'str | None'", DefVal: "None"},
+		}},
+		{"()", nil},
+		{"(a =", []*Arg{{Name: "a"}}},
+		{"(a) -> int", []*Arg{{Name: "a"}}},
+		{"(a: int)", []*Arg{{Name: "a", Type: "int"}}},
+		{"(a: int = 1, b: float)", []*Arg{{Name: "a", Type: "int", DefVal: "1"}, {Name: "b", Type: "float"}}},
+		{"(a = <1>, b = 2.0)", []*Arg{{Name: "a", DefVal: "<1>"}, {Name: "b", DefVal: "2.0"}}},
+		{"(a: 'Suffixes' = ('_x', '_y'))", []*Arg{{Name: "a", Type: "'Suffixes'", DefVal: "('_x', '_y')"}}},
+	}
+	for _, c := range cases {
+		args := Parse(c.sig)
+		if len(args) != len(c.args) {
+			t.Fatalf("%s: len(args) = %v, want %v", c.sig, len(args), len(c.args))
+		}
+		for i, arg := range args {
+			want := c.args[i]
+			if arg.Name != want.Name || arg.Type != want.Type || arg.DefVal != want.DefVal {
+				t.Fatalf("%s: args[%v] = %v, want %v", c.sig, i, arg, want)
+			}
+		}
+	}
+}