Support binary integers: 0b1101 literals and int("0b1101", 0) (#52)
* Support binary integers: 0b1101 literals and int("0b1101", 0)
* Specification and tests for binary integers
Adding documentation for bnary integers in spec.md.
Adding tests for syntax/scan_test.go (for the scanner) and testdata/int.sky for the int(x) function.
* Correct some test cases in syntax/scan_test.go
* Correct a test case in testdata/int.sky
diff --git a/doc/spec.md b/doc/spec.md
index e71ff5a..48b0ae2 100644
--- a/doc/spec.md
+++ b/doc/spec.md
@@ -294,6 +294,7 @@
123 # decimal int
0x7f # hexadecimal int
0755 # octal int
+0b1011 # binary int
0.0 0. .0 # float
1e10 1e+10 1e-10
@@ -307,10 +308,11 @@
Integer and floating-point literal tokens are defined by the following grammar:
```grammar {.good}
-int = decimal_lit | octal_lit | hex_lit .
+int = decimal_lit | octal_lit | hex_lit | binary_lit .
decimal_lit = ('1' … '9') {decimal_digit} .
octal_lit = '0' {octal_digit} .
hex_lit = '0' ('x'|'X') hex_digit {hex_digit} .
+binary_lit = '0' ('b'|'B') binary_digit {binary_digit} .
float = decimals '.' [decimals] [exponent]
| decimals exponent
@@ -320,8 +322,10 @@
exponent = ('e'|'E') ['+'|'-'] decimals .
decimal_digit = '0' … '9' .
+
octal_digit = '0' … '7' .
hex_digit = '0' … '9' | 'A' … 'F' | 'a' … 'f' .
+binary_digit = '0' | '1' .
```
TODO: define string_lit, indent, outdent, semicolon, newline, eof
diff --git a/library.go b/library.go
index 3503dc3..dd9a52e 100644
--- a/library.go
+++ b/library.go
@@ -589,6 +589,8 @@
hasbase = 8
case 'x', 'X':
hasbase = 16
+ case 'b', 'B':
+ hasbase = 2
}
if hasbase != 0 && b != 0 {
diff --git a/syntax/scan.go b/syntax/scan.go
index 1595b36..6b6c5e8 100644
--- a/syntax/scan.go
+++ b/syntax/scan.go
@@ -742,7 +742,7 @@
}
fraction = true
} else if c == '0' {
- // hex, octal, or float
+ // hex, octal, binary or float
sc.readRune()
c = sc.peekRune()
@@ -770,6 +770,17 @@
sc.readRune()
c = sc.peekRune()
}
+ } else if c == 'b' || c == 'B' {
+ // binary
+ sc.readRune()
+ c = sc.peekRune()
+ if !isbdigit(c) {
+ sc.error(sc.pos, "invalid binary literal")
+ }
+ for isbdigit(c) {
+ sc.readRune()
+ c = sc.peekRune()
+ }
} else {
// float (or obsolete octal "0755")
allzeros, octal := true, true
@@ -853,6 +864,8 @@
s := val.raw
if len(s) > 2 && s[0] == '0' && (s[1] == 'o' || s[1] == 'O') {
val.int, err = strconv.ParseInt(s[2:], 8, 64)
+ } else if len(s) > 2 && s[0] == '0' && (s[1] == 'b' || s[1] == 'B') {
+ val.int, err = strconv.ParseInt(s[2:], 2, 64)
} else {
val.int, err = strconv.ParseInt(s, 0, 64)
}
@@ -878,6 +891,7 @@
func isdigit(c rune) bool { return '0' <= c && c <= '9' }
func isodigit(c rune) bool { return '0' <= c && c <= '7' }
func isxdigit(c rune) bool { return isdigit(c) || 'A' <= c && c <= 'F' || 'a' <= c && c <= 'f' }
+func isbdigit(c rune) bool { return '0' == c || c == '1' }
// keywordToken records the special tokens for
// strings that should not be treated as ordinary identifiers.
diff --git a/syntax/scan_test.go b/syntax/scan_test.go
index 915f8be..6d1dba6 100644
--- a/syntax/scan_test.go
+++ b/syntax/scan_test.go
@@ -160,6 +160,13 @@
{"0XG", `foo.sky:1:1: invalid hex literal`},
{"0xA.", `10 . EOF`},
{"0xA.e1", `10 . e1 EOF`},
+ // binary
+ {"0b1010", `10 EOF`},
+ {"0B111101", `61 EOF`},
+ {"0b3", `foo.sky:1:3: invalid binary literal`},
+ {"0b1010201", `10 201 EOF`},
+ {"0b1010.01", `10 1.000000e-02 EOF`},
+ {"0b0000", `0 EOF`},
// octal
{"0o123", `83 EOF`},
{"0o12834", `10 834 EOF`},
diff --git a/testdata/int.sky b/testdata/int.sky
index ea51ffa..df11042 100644
--- a/testdata/int.sky
+++ b/testdata/int.sky
@@ -93,10 +93,15 @@
assert.eq(int("-12", 16), -18)
assert.eq(int("0x12", 16), 18)
assert.eq(int("-0x12", 16), -18)
+assert.eq(int("1010", 2), 10)
+assert.eq(int("111111101", 2), 509)
+assert.eq(int("0b0101", 0), 5)
+assert.eq(int("0b00000", 0), 0)
assert.fails(lambda: int("0x123", 8), "invalid literal.*base 8")
assert.fails(lambda: int("-0x123", 8), "invalid literal.*base 8")
assert.fails(lambda: int("0o123", 16), "invalid literal.*base 16")
assert.fails(lambda: int("-0o123", 16), "invalid literal.*base 16")
+assert.fails(lambda: int("0x110", 2), "invalid literal.*base 2")
# int from string, auto detect base
assert.eq(int("123", 0), 123)
assert.eq(int("+123", 0), +123)
