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26 lines
1.2 KiB
26 lines
1.2 KiB
Simple Expressions
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==================
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Literals
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--------
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A *literal* is a leaf in an expression; it is a value in the source of a Sol program which evaluates to itself. Literals in Sol come in exactly four flavors:
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* Integer literals, represented by contiguous digits, possibly preceded by a
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negation, like `0`, `123456`, `-314159`, and the like.
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* Floating point literals, represented by a pair of contiguous digits separated
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by one radix mark, again possibly preceded by a negation, like `1.0`,
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`-0.256`, `999.9`, and the like.
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* String literals, bound on either side by a single or double quote (they must
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match), and containing every interim character (including newline), like
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`"hello world"`, `'this string has two backslashes: \\'`, and the like.
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Naturally, a string may not contain its own terminator, though it can be
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introduced by concatenating strings with different terminators.
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* The special literal `None`, a value only ever equal to itself and which
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cannot be reassigned by the user program. It is frequently used to represent
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the absence of a value, such as the value of a function which does not
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explicitly return a value.
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The following source fragment demonstrates some of the literals::
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a = 123
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