fd14ab5694
Each side of '..' takes an optional bound marker, defaulting to
start-inclusive, end-exclusive (a..b == a=..<b; a..=b stays the short
end-inclusive spelling):
for 0<..<N (i) { } // 1 .. N-1 (both exclusive)
for 0=..=N (i) { } // 0 .. N (both inclusive)
for 0<..=N (i) { } // 1 .. N
for 0..<N (i) { } // 0 .. N-1 (explicit default)
for xs, 2<.. (x, i) // open range, exclusive start: i = 3, 4, ...
The nine lexemes are single tokens (maximal munch on '<'/'='/'..'), so
expression parsing never sees the leading marker as a comparison; '<',
'<<', '<=', '==', '=>' lex unchanged. An explicit end marker makes the
end expression mandatory; open forms are a.. / a<.. / a=... Works in
runtime, multi-iterable, and inline-for headers.
Regression: examples/0051-basic-for-range-bounds.sx (full matrix, open
start-marked ranges, comptime unroll, runtime bounds, lexer
non-regression); 1152's pinned message generalized.
49 lines
1.4 KiB
Plaintext
49 lines
1.4 KiB
Plaintext
// Range bound markers: each side of `..` takes `=` (inclusive) or `<`
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// (exclusive); defaults are start-inclusive, end-exclusive (`a..b` == `a=..<b`).
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// Covers the full matrix, open ranges with start markers, comptime unrolling,
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// runtime bounds, and that `<` / `<<` comparisons still lex normally.
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#import "modules/std.sx";
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main :: () -> s32 {
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for 0<..<5 (i) { print("{} ", i); }
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print("| 0<..<5\n");
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for 0=..=5 (i) { print("{} ", i); }
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print("| 0=..=5\n");
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for 0<..=5 (i) { print("{} ", i); }
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print("| 0<..=5\n");
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for 0=..<5 (i) { print("{} ", i); }
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print("| 0=..<5\n");
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for 0..<5 (i) { print("{} ", i); }
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print("| 0..<5\n");
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for 0..=5 (i) { print("{} ", i); }
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print("| 0..=5\n");
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// Exclusive-start open range following a bounded first iterable.
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xs : [3]s64 = .[10, 20, 30];
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for xs, 2<.. (x, i) { print("{}@{} ", x, i); }
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print("| xs, 2<..\n");
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// Explicit inclusive-start open form (synonym of `5..`).
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for xs, 5=.. (x, i) { print("{}@{} ", x, i); }
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print("| xs, 5=..\n");
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// Comptime-unrolled with markers.
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s := 0;
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inline for 0<..=3 (i) { s += i; }
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print("inline 0<..=3 sum={}\n", s);
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// Runtime bounds with markers.
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lo := 1;
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hi := 4;
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for lo<..=hi (i) { print("{} ", i); }
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print("| lo<..=hi\n");
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// Comparison operators still lex normally.
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a := 3;
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if a < 5 { print("cmp ok\n"); }
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b := a << 1;
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print("shl={}\n", b);
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0
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}
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