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Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 36 |
1 files changed, 36 insertions, 0 deletions
@@ -10086,6 +10086,42 @@ not be used as a function call; a function called apply (or similar) must be used for application even if the expression which gives the trailing arguments is a symbol. Moreover, applying sequences other than lists is not supported. +.NP* Improper Lists as Macro Calls + +\*(TL allows macros to be called using forms which are improper lists. +These forms are simply destructured by the usual macro parameter list +destructuring. To be callable this way, the macro must have an argument +list which specifies a parameter match in the dot position. This dot position +must either match the terminating atom of the improper list form, +or else match the trailing portion of the improper list form. + +For instance if a macro mac is defined as + +.cblk + (defmacro mac (a b . c) ...) +.cble + +then it may not be invoked as +.code "(mac 1 . 2)" +because the required argument +.code b +is not satisfied, and so the +.code 2 +argument cannot match the dot position +.code c +as required. The macro may be called as +.code "(mac 1 2 . 3)" +in which case +.code c +receives the form +.codn 3 . +If it is called as +.code "(mac 1 2 3 . 4)" +then +.code c +receives the improper list form +.codn "3 . 4" . + .NP* Regular Expression Literals In \*(TL, the .code / |