31 lines
656 B
Markdown
31 lines
656 B
Markdown
## Chapter 4: Lists
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Lists are enclosed in square brackets, and are finite sequences of elements.
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Elements can be anything: `[mia, robber(yolanda), X, 2, mia]` or `[mia,
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[vincent, jules], [butch, girlfriend(butch)]]` --- a list can contain other
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lists.
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Prolog lists use the standard head/tail vocabulary, and the decomposition operator is `|`:
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```
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[Head|Tail] = [mia, [vincent, jules], [butch, girlfriend(butch)]]
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```
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Note that the empty list behaves as one would think.
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```
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?- [X|Y] = [].
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no
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````
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Arguments can be chained, such as `[X, Y | Z]`.
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### The `member` function
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```
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member(X, [X|_]).
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member(X, [_|T]) :- member(X, T).
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```
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