34 lines
455 B
Markdown
34 lines
455 B
Markdown
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## dupdip
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Combinator
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Apply a function `F` and [dup] the item under it on the stack.
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a [F] dupdip
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------------------
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a F a
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### Definition
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> [dupd] [dip]
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### Derivation
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a [F] dupdip
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a [F] dupd dip
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a [F] [dup] dip dip
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a dup [F] dip
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a a [F] dip
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a F a
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### Discussion
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A very common and useful combinator.
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### Crosslinks
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[dupdipd]
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