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96 lines
2.6 KiB
Markdown
96 lines
2.6 KiB
Markdown
[< back to index](../index.md)
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# Literals and initializers
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## Numeric literals
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Decimal: `1`, `10`
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Binary: `%0101`, `0b101001`
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Quaternary: `0q2131`
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Octal: `0o172`
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Hexadecimal: `$D323`, `0x2a2`
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## String literals
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String literals are surrounded with double quotes and followed by the name of the encoding:
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"this is a string" ascii
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Characters between the quotes are interpreted literally,
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there are no ways to escape special characters or quotes.
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In some encodings, multiple characters are mapped to the same byte value,
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for compatibility with multiple variants.
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Currently available encodings:
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* `ascii` – standard ASCII
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* `pet` or `petscii` – PETSCII (ASCII-like character set used by Commodore machines)
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* `scr` – Commodore screencodes
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* `apple2` – Apple II charset ($A0–$FE)
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* `bbc` – BBC Micro and ZX Spectrum character set
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* `jis` or `jisx` – JIS X 0201
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* `iso_de`, `iso_no`, `iso_se`, `iso_yu` – various variants of ISO/IEC-646
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* `iso_dk`, `iso_fi` – aliases for `iso_no` and `iso_se` respectively
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When programming for Commodore,
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use `pet` for strings you're printing using standard I/O routines
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and `scr` for strings you're copying to screen memory directly.
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## Character literals
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Character literals are surrounded by single quotes and followed by the name of the encoding:
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'x' ascii
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From the type system point of view, they are constants of type byte.
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## Array initialisers
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An array is initialized with either:
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* a string literal
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* a `file` expression
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* a `for`-style expression
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* a format, followed by an array initializer:
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* `@word` (=`@word_le`): for every term of the array initializer, emit two bytes, first being the low byte of the value, second being the high byte:
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`@word [$1122]` is equivalent to `[$22, $11]`
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* `@word_be` – like the above, but opposite:
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`@word_be [$1122]` is equivalent to `[$11, $22]`
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* a list of byte literals and/or other array initializers, surrounded by brackets:
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array a = [1, 2]
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array b = "----" scr
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array c = ["hello world!" ascii, 13]
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array d = file("d.bin")
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array e = file("d.bin", 128, 256)
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array f = for x,0,until,8 [x * 3 + 5] // equivalent to [5, 8, 11, 14, 17, 20, 23, 26]
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Trailing commas (`[1, 2,]`) are not allowed.
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The parameters for `file` are: file path, optional start offset, optional length
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(start offset and length have to be either both present or both absent).
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The `for`-style expression has a variable, a starting index, a direction, a final index,
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and a parametrizable array initializer.
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The initializer is repeated for every value of the variable in the given range.
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