hare

commit c96533b97d7287ce978702dc73d3962195e38932
parent d09ea3b720bda1a31ba7bc7aa4095644ba271e6d
Author: Ember Sawady <ecs@d2evs.net>
Date:   Mon,  6 Nov 2023 21:08:00 +0000

fmt: add center-alignment

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

Diffstat:
M
fmt/+test.ha
 | 
3
+++
M
fmt/README
 | 
3
+++
M
fmt/iter.ha
 | 
2
++
M
fmt/print.ha
 | 
1
+

4 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/fmt/+test.ha b/fmt/+test.ha
@@ -66,6 +66,9 @@ use strconv;
 	assert(bsprintf(buf, "{:.1}", 123.0) == "100");
 	assert(bsprintf(buf, "{:.5}", 123.0) == "123");
 
+	assert(bsprintf(buf, "{:=5}", "hi") == "  hi ");
+	assert(bsprintf(buf, "{:=6}", "hi") == "  hi  ");
+
 	assert(bsprintf(buf, "{} {} {} {} {}", true, false, null, 'x', void)
 		== "true false (null) x void");
 };
diff --git a/fmt/README b/fmt/README
@@ -26,6 +26,9 @@ A format modifier can be any of the following:
   and the padding character is " " (a space).
 - "-": Left-align the value, inserting padding characters inserted on the right
   side of the value in order to meet the width requirement.
+- "=": Center-align the value, inserting the same amount of padding on the left
+  as on the right. If an odd number of padding characters need to be placed, the
+  extra one will be on the left of the value.
 - "_" followed by a rune: Use the given rune as the padding character rather
   than the default of " " (a space).
 - " " (a space): Insert a space before positive integers, where "-" would be if
diff --git a/fmt/iter.ha b/fmt/iter.ha
@@ -25,6 +25,7 @@ export type neg = enum {
 // Specifies how to align an argument within a given width.
 export type alignment = enum {
 	RIGHT,
+	CENTER,
 	LEFT,
 };
 
@@ -130,6 +131,7 @@ fn scan_modifiers(it: *iterator, mod: *mods) void = {
 	for (true) switch (getrune(it)) {
 	// alignment
 	case '-' => mod.alignment = alignment::LEFT;
+	case '=' => mod.alignment = alignment::CENTER;
 	// padding
 	case '_' => mod.pad = getrune(it);
 	// negation
diff --git a/fmt/print.ha b/fmt/print.ha
@@ -56,6 +56,7 @@ fn format(
 
 		switch (mod.alignment) {
 		case alignment::LEFT => abort();
+		case alignment::CENTER => start = (pad + 1) / 2;
 		case alignment::RIGHT => start = pad;
 		};
 	};