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29 lines
974 B
Markdown
29 lines
974 B
Markdown
# operator
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Operators are symbols that represent operations. Operands are things to the (left) right of an operator.
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Operators are a kind of function, and thus are themselves first-class objects that can be bound to variables. When binding, it is necessary to enclose it with ``.
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For `+` (and `-`), there are both unary and binary operators, so `_+_`(binary operation)/`+_`(unary operation ) must be specified.
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``` erg
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add = `+` # SyntaxError: specify `_+_` or `+_`
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add=`_+_`
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assert f(1, 2) == 3
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assert f("a", "b") == "ab"
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g = `*` # OK, this is binary only
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assert g(1, 2) == 2
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```
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Some fundamental operators, called special forms, cannot be bound.
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``` erg
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def = `=` # SyntaxError: cannot bind `=` operator, this is a special form
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# NG: def x, 1
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function = `->` # SyntaxError: cannot bind `->` operator, this is a special form
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# NG: function x, x + 1
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```
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<p align='center'>
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<a href='./05_builtin_funcs.md'>Previous</a> | <a href='./07_side_effect.md'>Next</a>
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</p>
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