builtin: string interpolation: binary format support (#11421)

vlib/builtin/string_int_test.v

@@ -219,3 +219,38 @@ fn test_signed_cast() {
 		assert '${u.f:G}' == '-INF'
 	}
 }
+
+fn test_binary() {
+	i := i8(127)
+	u := u8(127)
+	assert '${i:08b}' == '01111111'
+	assert '${u:08b}' == '01111111'
+	assert '${i16(i):08b}' == '01111111'
+	assert '${u16(u):08b}' == '01111111'
+	assert '${int(i):08b}' == '01111111'
+	assert '${u32(u):08b}' == '01111111'
+	assert '${i64(i):08b}' == '01111111'
+	assert '${u64(u):08b}' == '01111111'
+
+	n := i8(-1)
+	assert '${u8(-1):08b}' == '11111111'
+	assert '${u16(n):08b}' == '1111111111111111'
+	assert '${u32(n):08b}' == '11111111111111111111111111111111'
+	assert '${u64(n):08b}' == '1111111111111111111111111111111111111111111111111111111111111111'
+}
+
+fn test_binary32() {
+	i := int(0x7fff_ffff)
+	u := u32(0x7fff_ffff)
+	assert '${i:032b}' == '01111111111111111111111111111111'
+	assert '${u:032b}' == '01111111111111111111111111111111'
+	assert '${i64(i):032b}' == '01111111111111111111111111111111'
+	assert '${u64(u):032b}' == '01111111111111111111111111111111'
+}
+
+fn test_binary64() {
+	i := i64(0x7fff_ffff_ffff_ffff)
+	u := u64(0x7fff_ffff_ffff_ffff)
+	assert '${i:064b}' == '0111111111111111111111111111111111111111111111111111111111111111'
+	assert '${u:064b}' == '0111111111111111111111111111111111111111111111111111111111111111'
+}

vlib/builtin/string_interpolation.v

@@ -252,6 +252,10 @@ fn (data StrIntpData) get_fmt_format(mut sb strings.Builder) {
 				}
 				strconv.format_dec_sb(abs64(d), bf, mut sb)
 			} else {
+				// binary, we use 3 for binary
+				if base == 3 {
+					base = 2
+				}
 				mut hx := strconv.format_int(d, base)
 				if upper_case {
 					tmp := hx
@@ -287,6 +291,10 @@ fn (data StrIntpData) get_fmt_format(mut sb strings.Builder) {
 				}
 				strconv.format_dec_sb(d, bf, mut sb)
 			} else {
+				// binary, we use 3 for binary
+				if base == 3 {
+					base = 2
+				}
 				mut hx := strconv.format_uint(d, base)
 				if upper_case {
 					tmp := hx

vlib/v/checker/check_types.v

@@ -451,8 +451,7 @@ pub fn (mut c Checker) string_inter_lit(mut node ast.StringInterLiteral) ast.Typ
 		mut fmt := node.fmts[i]
 		// analyze and validate format specifier
 		if fmt !in [`E`, `F`, `G`, `e`, `f`, `g`, `d`, `u`, `x`, `X`, `o`, `c`, `s`, `S`, `p`,
-			`_`,
-		] {
+			`b`, `_`] {
 			c.error('unknown format specifier `${fmt:c}`', node.fmt_poss[i])
 		}
 		if fmt == `_` { // set default representation for type if none has been given
@@ -473,9 +472,10 @@ pub fn (mut c Checker) string_inter_lit(mut node ast.StringInterLiteral) ast.Typ
 			if node.pluss[i] && !typ.is_number() {
 				c.error('plus prefix only allowed for numbers', node.fmt_poss[i])
 			}
-			if (typ.is_unsigned() && fmt !in [`u`, `x`, `X`, `o`, `c`])
-				|| (typ.is_signed() && fmt !in [`d`, `x`, `X`, `o`, `c`])
-				|| (typ.is_int_literal() && fmt !in [`d`, `c`, `x`, `X`, `o`, `u`, `x`, `X`, `o`])
+			if (typ.is_unsigned() && fmt !in [`u`, `x`, `X`, `o`, `c`, `b`])
+				|| (typ.is_signed() && fmt !in [`d`, `x`, `X`, `o`, `c`, `b`])
+				|| (typ.is_int_literal()
+				&& fmt !in [`d`, `c`, `x`, `X`, `o`, `u`, `x`, `X`, `o`, `b`])
 				|| (typ.is_float() && fmt !in [`E`, `F`, `G`, `e`, `f`, `g`])
 				|| (typ.is_pointer() && fmt !in [`p`, `x`, `X`])
 				|| (typ.is_string() && fmt !in [`s`, `S`])

vlib/v/gen/c/str_intp.v

@@ -76,6 +76,10 @@ fn (mut g Gen) str_format(node ast.StringInterLiteral, i int) (u64, string) {
 		if fspec == `o` {
 			base = 8 - 2 // our base start from 2
 		}
+		// binary format
+		if fspec == `b` {
+			base = 1 // our base start from 2 we use 1 for binary
+		}
 		if fspec == `c` {
 			fmt_type = .si_c
 		} else {