hare

commit 5a1eed1cb0227e1dba686ef16a97baf7ac566057
parent c96533b97d7287ce978702dc73d3962195e38932
Author: Ember Sawady <ecs@d2evs.net>
Date:   Mon,  6 Nov 2023 21:08:01 +0000

fmt: flesh out float formatting

Signed-off-by: Ember Sawady <ecs@d2evs.net>

Diffstat:
M
fmt/+test.ha
 | 
10
++++++++++
M
fmt/README
 | 
11
+++++++++++
M
fmt/iter.ha
 | 
17
+++++++++++++++++
M
fmt/print.ha
 | 
4
++--

4 files changed, 40 insertions(+), 2 deletions(-)
diff --git a/fmt/+test.ha b/fmt/+test.ha
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: MPL-2.0
 // (c) Hare authors <https://harelang.org>
 
+use math;
 use strconv;
 
 @test fn print() void = {
@@ -66,6 +67,15 @@ use strconv;
 	assert(bsprintf(buf, "{:.1}", 123.0) == "100");
 	assert(bsprintf(buf, "{:.5}", 123.0) == "123");
 
+	assert(bsprintf(buf, "{:f}", 1.0e4) == "10000");
+	assert(bsprintf(buf, "{:e}", 123.45) == "1.2345e2");
+	assert(bsprintf(buf, "{:Fs}", 1.0) == "+1");
+	assert(bsprintf(buf, "{:F.}", 1.0) == "1.0");
+	assert(bsprintf(buf, "{:FU}", math::INF) == "INFINITY");
+	assert(bsprintf(buf, "{:FE}", 1.0e4) == "1E4");
+	assert(bsprintf(buf, "{:FS}", 1.0e4) == "1e+4");
+	assert(bsprintf(buf, "{:F2}", 1.0e4) == "1e04");
+
 	assert(bsprintf(buf, "{:=5}", "hi") == "  hi ");
 	assert(bsprintf(buf, "{:=6}", "hi") == "  hi  ");
 
diff --git a/fmt/README b/fmt/README
@@ -38,6 +38,17 @@ A format modifier can be any of the following:
 - "X": Format numbers in uppercase hexadecimal.
 - "o": Format numbers in octal.
 - "b": Format numbers in binary.
+- "e": Format floats in scientific notation.
+- "f": Format floats in fixed-point notation.
+- "g": Format floats in whichever of scientific and fixed-point notation is
+  shortest. This is the default.
+- "F" followed by "s": Use a sign for both positive and negative numbers.
+- "F" followed by ".": Always include at least one digit after the decimal
+  point.
+- "F" followed by "U": Uppercase INFINITY and NAN.
+- "F" followed by "E": Uppercase exponent symbols (E and P rather than e and p).
+- "F" followed by "S": Use a sign for both positive and negative exponents.
+- "F" followed by "2": Show at least two digits of the exponent.
 - "." followed by a number N: Sets the precision to N. Integers will be
   left-padded with "0"s between the sign and the number itself. Strings
   will be truncated to N runes. Floats will only include up to N digits after
diff --git a/fmt/iter.ha b/fmt/iter.ha
@@ -37,6 +37,8 @@ export type mods = struct {
 	width: size,
 	prec: size,
 	base: strconv::base,
+	ffmt: strconv::ffmt,
+	fflags: strconv::fflags,
 };
 
 type iterator = struct {
@@ -142,6 +144,21 @@ fn scan_modifiers(it: *iterator, mod: *mods) void = {
 	case 'X' => mod.base = strconv::base::HEX_UPPER;
 	case 'o' => mod.base = strconv::base::OCT;
 	case 'b' => mod.base = strconv::base::BIN;
+	// ffmt
+	case 'e' => mod.ffmt = strconv::ffmt::E;
+	case 'f' => mod.ffmt = strconv::ffmt::F;
+	case 'g' => mod.ffmt = strconv::ffmt::G;
+	// fflags
+	case 'F' =>
+		switch (getrune(it)) {
+		case 's' => mod.fflags |= strconv::fflags::SHOW_POS;
+		case '.' => mod.fflags |= strconv::fflags::SHOW_POINT;
+		case 'U' => mod.fflags |= strconv::fflags::UPPERCASE;
+		case 'E' => mod.fflags |= strconv::fflags::UPPER_EXP;
+		case 'S' => mod.fflags |= strconv::fflags::SHOW_POS_EXP;
+		case '2' => mod.fflags |= strconv::fflags::SHOW_TWO_EXP_DIGITS;
+		case => abort("Invalid float flag");
+		};
 	// precision
 	case '.' => mod.prec = scan_sz(it);
 	// width
diff --git a/fmt/print.ha b/fmt/print.ha
@@ -106,8 +106,8 @@ case let f: types::floating =>
 		|| mod.base == strconv::base::DEC); // TODO
 	assert(mod.prec <= types::UINT_MAX);
 	// TODO: mod.prec should be (size | void) but that needs @default
-	return strconv::fftosf(out, f, strconv::ffmt::G,
-		if (mod.prec != 0) mod.prec: uint else void, 0)?;
+	return strconv::fftosf(out, f, mod.ffmt,
+		if (mod.prec != 0) mod.prec: uint else void, mod.fflags)?;
 case let i: types::integer =>
 	let neg = match (i) {
 	case types::unsigned =>