all: new string interpolation in pure V (#10181)

vlib/builtin/float.v

@@ -12,6 +12,17 @@ import strconv
 // str return a `f64` as `string` in suitable notation.
 [inline]
 pub fn (x f64) str() string {
+	unsafe {
+		f := strconv.Float64u{
+			f: x
+		}
+		if f.u == strconv.double_minus_zero {
+			return '-0'
+		}
+		if f.u == strconv.double_plus_zero {
+			return '0'
+		}
+	}
 	abs_x := f64_abs(x)
 	if abs_x >= 0.0001 && abs_x < 1.0e6 {
 		return strconv.f64_to_str_l(x)
@@ -20,6 +31,20 @@ pub fn (x f64) str() string {
 	}
 }
 
+// strg return a `f64` as `string` in "g" printf format
+[inline]
+pub fn (x f64) strg() string {
+	if x == 0 {
+		return '0'
+	}
+	abs_x := f64_abs(x)
+	if abs_x >= 0.0001 && abs_x < 1.0e6 {
+		return strconv.f64_to_str_l_no_dot(x)
+	} else {
+		return strconv.ftoa_64(x)
+	}
+}
+
 // str returns the value of the `float_literal` as a `string`.
 [inline]
 pub fn (d float_literal) str() string {
@@ -53,6 +78,17 @@ pub fn (x f64) strlong() string {
 // str returns a `f32` as `string` in suitable notation.
 [inline]
 pub fn (x f32) str() string {
+	unsafe {
+		f := strconv.Float32u{
+			f: x
+		}
+		if f.u == strconv.single_minus_zero {
+			return '-0'
+		}
+		if f.u == strconv.single_plus_zero {
+			return '0'
+		}
+	}
 	abs_x := f32_abs(x)
 	if abs_x >= 0.0001 && abs_x < 1.0e6 {
 		return strconv.f32_to_str_l(x)
@@ -61,6 +97,20 @@ pub fn (x f32) str() string {
 	}
 }
 
+// strg return a `f32` as `string` in "g" printf format
+[inline]
+pub fn (x f32) strg() string {
+	if x == 0 {
+		return '0'
+	}
+	abs_x := f32_abs(x)
+	if abs_x >= 0.0001 && abs_x < 1.0e6 {
+		return strconv.f32_to_str_l_no_dot(x)
+	} else {
+		return strconv.ftoa_32(x)
+	}
+}
+
 // strsci returns the `f32` as a `string` in scientific notation with `digit_num` deciamals displayed, max 8 digits.
 // Example: assert f32(1.234).strsci(3) == '1.234e+00'
 [inline]