Calls and returns

A definition can be called simply be writing the name of the definition to be called. Note that normally a definition is invisible during its definition. If you want to write a directly recursive definition, you can use recursive to make the current definition visible.

recursive       compilation -- ; run-time --         gforth       ``recursive''

makes the current definition visible, enabling it to call itself recursively.

Another way to perform a recursive call is

recurse       compilation -- ; run-time ?? -- ??         core       ``recurse''

calls the current definition.

@progstyle I prefer using recursive to recurse, because calling the definition by name is more descriptive (if the name is well-chosen) than the somewhat cryptic recurse. E.g., in a quicksort implementation, it is much better to read (and think) "now sort the partitions" than to read "now do a recursive call".

For mutual recursion, use deferred words, like this:

defer foo

: bar ( ... -- ... )
 ... foo ... ;

:noname ( ... -- ... )
 ... bar ... ;
IS foo

When the end of the definition is reached, it returns. An earlier return can be forced using

EXIT       compilation -- ; run-time nest-sys --         core       ``EXIT''

Don't forget to clean up the return stack and UNLOOP any outstanding ?DO...LOOPs before EXITing. The primitive compiled by EXIT is

;s       --       gforth       ``semis''

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