builtin: Implement builtin_ascii

Implement builtin ascii

Author: corona10

builtin/builtin.go

@@ -6,6 +6,9 @@
 package builtin
 
 import (
+	"strconv"
+	"strings"
+	"unicode"
 	"unicode/utf8"
 
 	"github.com/go-python/gpython/compile"
@@ -24,7 +27,7 @@ func init() {
 		py.MustNewMethod("abs", builtin_abs, 0, abs_doc),
 		py.MustNewMethod("all", builtin_all, 0, all_doc),
 		py.MustNewMethod("any", builtin_any, 0, any_doc),
-		// py.MustNewMethod("ascii", builtin_ascii, 0, ascii_doc),
+		py.MustNewMethod("ascii", builtin_ascii, 0, ascii_doc),
 		// py.MustNewMethod("bin", builtin_bin, 0, bin_doc),
 		// py.MustNewMethod("callable", builtin_callable, 0, callable_doc),
 		py.MustNewMethod("chr", builtin_chr, 0, chr_doc),
@@ -309,6 +312,36 @@ func builtin_any(self, seq py.Object) (py.Object, error) {
 	return py.False, nil
 }
 
+const ascii_doc = `ascii(obj, /)
+Return an ASCII-only representation of an object.
+
+As repr(), return a string containing a printable representation of an
+object, but escape the non-ASCII characters in the string returned by
+repr() using \\x, \\u or \\U escapes. This generates a string similar
+to that returned by repr() in Python 2
+`
+
+func builtin_ascii(self, o py.Object) (py.Object, error) {
+	reprObject, err := py.Repr(o)
+	if err != nil {
+		return nil, err
+	}
+
+	var sb strings.Builder
+	repr := reprObject.(py.String)
+	for _, c := range repr {
+		if c <= unicode.MaxASCII {
+			sb.WriteRune(c)
+		} else {
+			s := "\\u" + strconv.FormatInt(int64(c), 16)
+			sb.WriteString(s)
+		}
+	}
+
+	ascii := sb.String()
+	return py.String(ascii), nil
+}
+
 const round_doc = `round(number[, ndigits]) -> number
 
 Round a number to a given precision in decimal digits (default 0 digits).

builtin/tests/builtin.py

@@ -19,6 +19,10 @@
 assert any(["hello", "world"]) == True
 assert any([]) == False
 
+doc="ascii"
+assert ascii('hello world') == "'hello world'"
+assert ascii('안녕 세상') == "'\\uc548\\ub155 \\uc138\\uc0c1'"
+
 doc="chr"
 assert chr(65) == "A"
 assert chr(163) == "£"