diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 34 |
1 files changed, 28 insertions, 6 deletions
@@ -8153,12 +8153,13 @@ can be expressed as: (mapcar function (conses list0) (conses list1) ... (conses listn)) -.SS Function apply +.SS Functions apply and iapply .TP Syntax: (apply <function> [ <arg>* <trailing-args> ]) + (iapply <function> [ <arg>* <trailing-args> ]) .TP Description: @@ -8180,6 +8181,16 @@ these arguments is interpreted as <trailing-args>. The previous arguments represent leading arguments which are applied to <function>, prior to the arguments taken from <trailing-args>. +The iapply function ("improper apply") is similar to apply, except with regard +to the treatment of <trailing-args>. Firstly, under iapply, if <trailing-args> +is an atom other than nil (possibly a sequence, such as a vector or string), +then it is treated as an ordinary argument: <function> is invoked with a proper +argument list, whose last element is <trailing-args>. Secondly, if +<trailing-args> is a list, but an improper list, then the terminating atom of +<trailing-args> becomes an ordinary argument. Thus, in all possible cases, +iapply treats an extra non-nil atom as an argument, and never calls +<function> with an improper argument list. + .TP Examples: @@ -12003,12 +12014,13 @@ is the first argument of the inner function. Of course, if there are three levels of nesting, then three metas are needed to insert a parameter from the outermost op, into the innermost op. -.SS Macro ap +.SS Macros ap and ip .TP Syntax: (ap <form>+) + (ip <form>+) .TP Description: @@ -12016,7 +12028,7 @@ Description: The ap macro is based on the op macro and has identical argument conventions. -The ap macro analyzes its argumetns and produces a function, in exactly the +The ap macro analyzes its arguments and produces a function, in exactly the same same way as the op macro. It then returns a different one-argument function which accepts a list, and calls that function, applying the list as arguments. @@ -12030,7 +12042,13 @@ except that the symbol args is to be understood as a generated symbol (gensym). The ap macro nests properly with op and do, in any combination, in regard to the @@n notation. -See also: the apf function. +The ip macro is very similar to the ap macro, except that it is based +on the semantics of the function iapply rather than apply, according +to the following equivalence: + + (ap form ...) <--> (lambda (args) (iapply (op form ...))) + +See also: the apf function .SS Macro ret @@ -12232,21 +12250,25 @@ Example: ;; the function returned by (retf 42) ignores 1 2 3 and returns 42. (call (retf 42) 1 2 3) -> 42 -.SH Function apf +.SH Functions apf and ipf .TP Syntax: (apf <function>) + (ipf <function>) .TP Description: The apf function returns a one-argument function which accepts a list. When the function is called, it treats the list as -argument which are applied to <function>. It returns whatever +argument which are applied to <function> as if by apply. It returns whatever <function> returns. +The ipf function is similar to apf, except that the returned +function applies arguments as if by iapply rather than apply. + See also: the ap macro. .TP |