diff options
Diffstat (limited to 'starlark/library.go')
| -rw-r--r-- | starlark/library.go | 154 |
1 files changed, 76 insertions, 78 deletions
diff --git a/starlark/library.go b/starlark/library.go index 1763824..5645418 100644 --- a/starlark/library.go +++ b/starlark/library.go @@ -473,114 +473,112 @@ func int_(thread *Thread, _ *Builtin, args Tuple, kwargs []Tuple) (Value, error) return nil, err } - // "If x is not a number or base is given, x must be a string." if s, ok := AsString(x); ok { b := 10 if base != nil { var err error b, err = AsInt32(base) - if err != nil || b != 0 && (b < 2 || b > 36) { + if err != nil { + return nil, fmt.Errorf("int: for base, got %s, want int", base.Type()) + } + if b != 0 && (b < 2 || b > 36) { return nil, fmt.Errorf("int: base must be an integer >= 2 && <= 36") } } + res := parseInt(s, b) + if res == nil { + return nil, fmt.Errorf("int: invalid literal with base %d: %s", b, s) + } + return res, nil + } - orig := s // save original for error message + if base != nil { + return nil, fmt.Errorf("int: can't convert non-string with explicit base") + } - // remove sign - var neg bool - if s != "" { - if s[0] == '+' { - s = s[1:] - } else if s[0] == '-' { - neg = true - s = s[1:] - } + if b, ok := x.(Bool); ok { + if b { + return one, nil + } else { + return zero, nil } + } - // remove base prefix - baseprefix := 0 - if len(s) > 1 && s[0] == '0' { - if len(s) > 2 { - switch s[1] { - case 'o', 'O': - s = s[2:] - baseprefix = 8 - case 'x', 'X': - s = s[2:] - baseprefix = 16 - case 'b', 'B': - s = s[2:] - baseprefix = 2 - } - } + i, err := NumberToInt(x) + if err != nil { + return nil, fmt.Errorf("int: %s", err) + } + return i, nil +} +// parseInt defines the behavior of int(string, base=int). It returns nil on error. +func parseInt(s string, base int) Value { + // remove sign + var neg bool + if s != "" { + if s[0] == '+' { + s = s[1:] + } else if s[0] == '-' { + neg = true + s = s[1:] + } + } + + // remove optional base prefix + baseprefix := 0 + if len(s) > 1 && s[0] == '0' { + if len(s) > 2 { + switch s[1] { + case 'o', 'O': + baseprefix = 8 + case 'x', 'X': + baseprefix = 16 + case 'b', 'B': + baseprefix = 2 + } + } + if baseprefix != 0 { + // Remove the base prefix if it matches + // the explicit base, or if base=0. + if base == 0 || baseprefix == base { + base = baseprefix + s = s[2:] + } + } else { // For automatic base detection, // a string starting with zero // must be all zeros. // Thus we reject int("0755", 0). - if baseprefix == 0 && b == 0 { + if base == 0 { for i := 1; i < len(s); i++ { if s[i] != '0' { - goto invalid + return nil } } - return zero, nil - } - - if b != 0 && baseprefix != 0 && baseprefix != b { - // Explicit base doesn't match prefix, - // e.g. int("0o755", 16). - goto invalid + return zero } } - - // select base - if b == 0 { - if baseprefix != 0 { - b = baseprefix - } else { - b = 10 - } - } - - // we explicitly handled sign above. - // if a sign remains, it is invalid. - if s != "" && (s[0] == '-' || s[0] == '+') { - goto invalid - } - - // s has no sign or base prefix. - // - // int(x) permits arbitrary precision, unlike the scanner. - if i, ok := new(big.Int).SetString(s, b); ok { - res := MakeBigInt(i) - if neg { - res = zero.Sub(res) - } - return res, nil - } - - invalid: - return nil, fmt.Errorf("int: invalid literal with base %d: %s", b, orig) + } + if base == 0 { + base = 10 } - if base != nil { - return nil, fmt.Errorf("int: can't convert non-string with explicit base") + // we explicitly handled sign above. + // if a sign remains, it is invalid. + if s != "" && (s[0] == '-' || s[0] == '+') { + return nil } - if b, ok := x.(Bool); ok { - if b { - return one, nil - } else { - return zero, nil + // s has no sign or base prefix. + if i, ok := new(big.Int).SetString(s, base); ok { + res := MakeBigInt(i) + if neg { + res = zero.Sub(res) } + return res } - i, err := NumberToInt(x) - if err != nil { - return nil, fmt.Errorf("int: %s", err) - } - return i, nil + return nil } // https://github.com/google/starlark-go/blob/master/doc/spec.md#len |