commit ebfbd177278350b9bef485063c09b09dc545e3bb
parent 2d00164aec76d18da24bb53f63e1ac868607b433
Author: Drew DeVault <sir@cmpwn.com>
Date: Fri, 5 Feb 2021 12:05:12 -0500
fmt: implement numbered arguments
Diffstat:
| M | fmt/fmt.ha | | | 50 | +++++++++++++++++++++++++++++++++++++++++--------- |
1 file changed, 41 insertions(+), 9 deletions(-)
diff --git a/fmt/fmt.ha b/fmt/fmt.ha
@@ -9,6 +9,7 @@
// manner: '{0:x} will print a number in hexadecimal.
//
// TODO: More detail
+use ascii;
use encoding::utf8;
use io;
use os;
@@ -19,6 +20,14 @@ use types;
// Tagged union of all types which are formattable.
export type formattable = (...types::numeric | uintptr | str | *void);
+// Formats text for printing writes it to [os::stdout].
+export fn printf(fmt: str, args: formattable...) (io::error | size) =
+ fprintf(os::stdout, fmt, args...);
+
+// Formats text for printing writes it to [os::stderr].
+export fn errorf(fmt: str, args: formattable...) (io::error | size) =
+ fprintf(os::stderr, fmt, args...);
+
// Formats text for printing and writes it to an [io::stream].
export fn fprintf(
s: *io::stream,
@@ -38,8 +47,18 @@ export fn fprintf(
void => abort("Invalid format string (unterminated '{')"),
r: rune => r,
};
- assert(r == '}'); // TODO
- format(s, args[i]);
+
+ let arg = args[i];
+ switch (r) {
+ ':' => abort(), // TODO: format specifiers
+ '}' => void,
+ * => {
+ i -= 1z;
+ arg = args[scan_uint(r, &iter)];
+ },
+ };
+
+ format(s, arg);
i += 1z;
continue;
};
@@ -55,13 +74,26 @@ export fn fprintf(
return n;
};
-// Formats text for printing writes it to [os::stdout].
-export fn printf(fmt: str, args: formattable...) (io::error | size) =
- fprintf(os::stdout, fmt, args...);
-
-// Formats text for printing writes it to [os::stderr].
-export fn errorf(fmt: str, args: formattable...) (io::error | size) =
- fprintf(os::stderr, fmt, args...);
+fn scan_uint(r: rune, iter: *strings::iterator) uint = {
+ assert(ascii::isdigit(r));
+ let num = alloc([]u8, [r: u32: u8], 1z); // XXX: alloc slice w/o cap
+ for (true) {
+ r = match (strings::next(iter)) {
+ void => abort("Invalid format string (unterminated '(')"),
+ r: rune => r,
+ };
+ switch (r) {
+ * => append(num, r: u32: u8),
+ ':' => abort(), // TODO: Format specifiers
+ '}' => match (strconv::stou(strings::from_utf8(num))) {
+ (strconv::invalid | strconv::overflow) =>
+ abort("Invalid format string (invalid index)"),
+ u: uint => return u,
+ },
+ };
+ };
+ abort("unreachable");
+};
fn format(out: *io::stream, arg: formattable) void = match (arg) {
s: str => io::write(out, strings::to_utf8(s)),
