cond-expand

[syntax] cond-expand cond-expand-clause ...

SRFI-0: The cond-expand form tests for the existence of features at macro-expansion time. It either expands into the body of one of its clauses or signals an error during syntactic processing. cond-expand expands into the body of the first clause whose feature requirement is currently satisfied (the else clause, if present, is selected if none of the previous clauses is selected).

Besides various srfi-N feature identifiers, some implementations define more identifiers.

Chicken

feature 'chicken' is defined. Also feature 'compiling' is defined during compilation.

Gauche

featuer 'gauche' is defined.