builtin: add is_hex(), is_int(), is_bin(), and is_oct() methods to the string type (#20540)

vlib/builtin/string.v

@@ -1786,6 +1786,149 @@ fn (s string) at_with_check(idx int) ?u8 {
 	}
 }
 
+// Check if a string is an octal value. Returns 'true' if it is, or 'false' if it is not
+@[direct_array_access]
+pub fn (str string) is_oct() bool {
+	mut i := 0
+
+	if str[i] == `0` {
+		i++
+	} else if str[i] == `-` || str[i] == `+` {
+		i++
+
+		if str[i] == `0` {
+			i++
+		} else {
+			return false
+		}
+	} else {
+		return false
+	}
+
+	if str[i] == `o` {
+		i++
+	} else {
+		return false
+	}
+
+	if i == str.len {
+		return false
+	}
+
+	for i < str.len {
+		if str[i] < `0` || str[i] > `7` {
+			return false
+		}
+		i++
+	}
+
+	return true
+}
+
+// Check if a string is an binary value. Returns 'true' if it is, or 'false' if it is not
+@[direct_array_access]
+pub fn (str string) is_bin() bool {
+	mut i := 0
+
+	if str[i] == `0` {
+		i++
+	} else if str[i] == `-` || str[i] == `+` {
+		i++
+
+		if str[i] == `0` {
+			i++
+		} else {
+			return false
+		}
+	} else {
+		return false
+	}
+
+	if str[i] == `b` {
+		i++
+	} else {
+		return false
+	}
+
+	if i == str.len {
+		return false
+	}
+
+	for i < str.len {
+		if str[i] < `0` || str[i] > `1` {
+			return false
+		}
+		i++
+	}
+
+	return true
+}
+
+// Check if a string is an hexadecimal value. Returns 'true' if it is, or 'false' if it is not
+@[direct_array_access]
+pub fn (str string) is_hex() bool {
+	mut i := 0
+
+	if str[i] == `0` {
+		i++
+	} else if str[i] == `-` || str[i] == `+` {
+		i++
+
+		if str[i] == `0` {
+			i++
+		} else {
+			return false
+		}
+	} else {
+		return false
+	}
+
+	if str[i] == `x` {
+		i++
+	} else {
+		return false
+	}
+
+	if i == str.len {
+		return false
+	}
+
+	for i < str.len {
+		if (str[i] < `0` || str[i] > `9`) && ((str[i] < `a` || str[i] > `f`)
+			&& (str[i] < `A` || str[i] > `F`)) {
+			return false
+		}
+		i++
+	}
+
+	return true
+}
+
+// Check if a string is an integer value. Returns 'true' if it is, or 'false' if it is not
+@[direct_array_access]
+pub fn (str string) is_int() bool {
+	mut i := 0
+
+	if (str[i] != `-` && str[i] != `+`) && (!str[i].is_digit()) {
+		return false
+	} else {
+		i++
+	}
+
+	if i == str.len && (!str[i - 1].is_digit()) {
+		return false
+	}
+
+	for i < str.len {
+		if str[i] < `0` || str[i] > `9` {
+			return false
+		}
+		i++
+	}
+
+	return true
+}
+
 // is_space returns `true` if the byte is a white space character.
 // The following list is considered white space characters: ` `, `\t`, `\n`, `\v`, `\f`, `\r`, 0x85, 0xa0
 // Example: assert u8(` `).is_space() == true

vlib/builtin/string_test.v

@@ -425,6 +425,168 @@ fn test_rsplit_once() ? {
 	assert ext3 == ''
 }
 
+fn test_is_bin() {
+	assert '0b1'.is_bin() == true
+	assert '0b0'.is_bin() == true
+	assert '0b'.is_bin() == false
+	assert '-0b'.is_bin() == false
+	assert '-0b1'.is_bin() == true
+	assert '-0b0'.is_bin() == true
+	assert '-0b1101'.is_bin() == true
+	assert '-0b0101'.is_bin() == true
+	assert '-324'.is_bin() == false
+	assert '-0'.is_bin() == false
+	assert '0x1'.is_bin() == false
+	assert '0x1A'.is_bin() == false
+	assert '+0b1101'.is_bin() == true
+	assert '+0b1'.is_bin() == true
+	assert '-0x1'.is_bin() == false
+	assert '-0x1A'.is_bin() == false
+	assert '0x'.is_bin() == false
+	assert '0'.is_bin() == false
+	assert '0xFF'.is_bin() == false
+	assert '0xG'.is_bin() == false
+	assert '-'.is_bin() == false
+	assert '+'.is_bin() == false
+	assert '-0xFF'.is_bin() == false
+	assert '0.34'.is_bin() == false
+	assert '0o23'.is_bin() == false
+	assert 'vlang'.is_bin() == false
+}
+
+fn test_is_oct() {
+	assert '0o0'.is_oct() == true
+	assert '0o1'.is_oct() == true
+	assert '0o2'.is_oct() == true
+	assert '-0o0'.is_oct() == true
+	assert '-0o1'.is_oct() == true
+	assert '-0o2'.is_oct() == true
+
+	assert '0o04'.is_oct() == true
+	assert '0o16'.is_oct() == true
+	assert '0o23'.is_oct() == true
+	assert '-0o05'.is_oct() == true
+	assert '-0o13'.is_oct() == true
+	assert '-0o22'.is_oct() == true
+
+	assert '0o8'.is_oct() == false
+	assert '0o9'.is_oct() == false
+	assert '-0o8'.is_oct() == false
+	assert '-0o9'.is_oct() == false
+	assert '0o84'.is_oct() == false
+	assert '0o96'.is_oct() == false
+	assert '-0o83'.is_oct() == false
+	assert '-0o2923'.is_oct() == false
+	assert '0b1'.is_oct() == false
+	assert '0b0'.is_oct() == false
+	assert '0b'.is_oct() == false
+	assert '-0b'.is_oct() == false
+	assert '-0b1'.is_oct() == false
+	assert '-0b0'.is_oct() == false
+	assert '-0b1101'.is_oct() == false
+	assert '+0o234'.is_oct() == true
+	assert '+0o432'.is_oct() == true
+	assert '-'.is_oct() == false
+	assert '+'.is_oct() == false
+	assert '-0b0101'.is_oct() == false
+	assert '-324'.is_oct() == false
+	assert '-0'.is_oct() == false
+	assert '0x1'.is_oct() == false
+	assert '0x1A'.is_oct() == false
+	assert '-0x1'.is_oct() == false
+	assert '-0x1A'.is_oct() == false
+	assert '0x'.is_oct() == false
+	assert '0'.is_oct() == false
+	assert '0xFF'.is_oct() == false
+	assert '0xG'.is_oct() == false
+	assert '-0xFF'.is_oct() == false
+	assert '0.34'.is_oct() == false
+	assert 'vlang'.is_oct() == false
+}
+
+fn test_is_hex() {
+	assert '-324'.is_hex() == false
+	assert '-0'.is_hex() == false
+	assert '0x1'.is_hex() == true
+	assert '0x1A'.is_hex() == true
+	assert '-0x1'.is_hex() == true
+	assert '-0x1A'.is_hex() == true
+	assert '+0x1'.is_hex() == true
+	assert '+0x1A'.is_hex() == true
+	assert '0x'.is_hex() == false
+	assert '0'.is_hex() == false
+	assert '-'.is_hex() == false
+	assert '+'.is_hex() == false
+	assert '0xFF'.is_hex() == true
+	assert '0xG'.is_hex() == false
+	assert '-0xFF'.is_hex() == true
+	assert '0b1101'.is_hex() == false
+	assert '0.34'.is_hex() == false
+	assert '0o23'.is_hex() == false
+	assert 'vlang'.is_hex() == false
+}
+
+fn test_is_int() {
+	assert '-324'.is_int() == true
+	assert '234'.is_int() == true
+	assert '-0'.is_int() == true
+	assert '-b'.is_int() == false
+	assert '-123456789'.is_int() == true
+	assert '123456789'.is_int() == true
+	assert '0x1'.is_int() == false
+	assert '0b1101'.is_int() == false
+	assert '0.34'.is_int() == false
+	assert '0o23'.is_int() == false
+	assert 'vlang'.is_int() == false
+
+	assert '0o0'.is_int() == false
+	assert '0o1'.is_int() == false
+	assert '0o2'.is_int() == false
+	assert '-0o0'.is_int() == false
+	assert '-0o1'.is_int() == false
+	assert '-0o2'.is_int() == false
+
+	assert '0o04'.is_int() == false
+	assert '0o16'.is_int() == false
+	assert '0o23'.is_int() == false
+	assert '-0o05'.is_int() == false
+	assert '-0o13'.is_int() == false
+	assert '-0o22'.is_int() == false
+
+	assert '0o8'.is_int() == false
+	assert '0o9'.is_int() == false
+	assert '-0o8'.is_int() == false
+	assert '-0o9'.is_int() == false
+	assert '0o84'.is_int() == false
+	assert '0o96'.is_int() == false
+	assert '-0o83'.is_int() == false
+	assert '-0o2923'.is_int() == false
+	assert '0b1'.is_int() == false
+	assert '0b0'.is_int() == false
+	assert '0b'.is_int() == false
+	assert '-0b'.is_int() == false
+	assert '-0b1'.is_int() == false
+	assert '-0b0'.is_int() == false
+	assert '-0b1101'.is_int() == false
+	assert '-0b0101'.is_int() == false
+	assert '-324'.is_int() == true
+	assert '-0'.is_int() == true
+	assert '0x1'.is_int() == false
+	assert '0x1A'.is_int() == false
+	assert '-0x1'.is_int() == false
+	assert '-0x1A'.is_oct() == false
+	assert '0x'.is_int() == false
+	assert '0'.is_int() == true
+	assert '0xFF'.is_int() == false
+	assert '0xG'.is_int() == false
+	assert '-0xFF'.is_int() == false
+	assert '0.34'.is_int() == false
+	assert '-'.is_int() == false
+	assert '+'.is_int() == false
+	assert '+3'.is_int() == true
+	assert '+3232'.is_int() == true
+}
+
 fn test_trim_space() {
 	a := ' a '
 	assert a.trim_space() == 'a'