12 lines
537 B
Plaintext
12 lines
537 B
Plaintext
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parameter (or string (option int));
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storage unit;
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return string;
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code { CAR; # Access the storage
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IF_LEFT {} # The string is on top of the stack, nothing to do
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{ IF_NONE { FAIL} # Fail if None
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{ PUSH int 0; CMPGT; # Check for negative number
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IF {FAIL} # Fail if negative
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{PUSH string ""}}}; # Push the empty string
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UNIT; SWAP; PAIR} # Calling convention
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