diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 44 |
1 files changed, 29 insertions, 15 deletions
@@ -35395,11 +35395,16 @@ paragraph regarding the evaluation scope of .RE .IP -Arguments to keyword appear as a property list which begins -after the last required or optional argument. A property list -consists of interleaved indicators and values. The indicators -for keyword parameters are keyword symbols whose names match -the parameter names. For instance, the indicator-value pair +In a call to a +.codn :key -enabled +function, keyword arguments begin after those arguments which satisfy +all of the required and optional parameters. Keyword arguments consist +of interleaved indicators and values, which are separate arguments. +Thus passing a keyword argument actually requires the passing of two +function arguments: an indicator keyword symbol, followed by the +associated value. The indicator keywords are expected to have the +same symbol name as the defined keyword parameters. For instance, the +indicator-value pair .code ":xyz 42" passes the value .code 42 @@ -35410,22 +35415,31 @@ in any package: it may be or .code mypackage:xyz and so forth. +Arguments specifying unrecognized keywords are ignored. If the function has a -.meta rest-param -then that param receives the keyword parameter list. That is to say, the +.metn rest-param , +then that parameter receives the keyword arguments as a list. +Since that list contains indicators and values, it is a +.I "de facto" +property list. In detail, the .code :key mechanism generates a regular variadic function which receives the keyword -parameters as the trailing arguments. The function is endowed with code which -parses these extra arguments out of the trailing list, and binds them to -the keyword parameter symbols. If a +arguments as the trailing argument list. That function +parses the recognized keyword arguments out of the trailing list, and +binds them to the keyword parameter symbols as local variables. If a .meta rest-param -argument present, then it specifies a symbol to be used as the name of -the rest parameter, making the entire keyword argument list available -under that name. If there is no +parameter is defined, then the entire keyword argument list is available +through that parameter, and the keyword argument parsing logic also refers to +the value of that parameter to gain access to the keyword arguments. If +there is no +.meta rest-param +specified, then the +.code :key +macro adds a .meta rest-param -then a machine-generated rest parameter is substituted; the keyword argument -parsing logic refers to that instead. +using a machine-generated symbol. The argument parsing logic then +refers to the value of that symbol. .TP* Example: |