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| -rw-r--r-- | ChangeLog | 4 | ||||
| -rw-r--r-- | txr.1 | 40 |
2 files changed, 32 insertions, 12 deletions
@@ -1,3 +1,7 @@ +2014-02-27 Kaz Kylheku <kaz@kylheku.com> + + * txr.1: Improved documentation for the dwim operator. + 2014-02-26 Kaz Kylheku <kaz@kylheku.com> Version 82 @@ -5606,18 +5606,34 @@ The dwim operator takes a variable number of arguments, which are all evaluated in the same way: the first argument is not evaluated differently from the remaining arguments. -Furthermore, the evaluation of symbols is done differently: all of the -enclosing scopes are considered as if the function and variable namespaces are -collapsed into a single namespace, in which variable names take precedence over -functions if there exist mutiple bindings. This allows functions to be -referenced without the fun operator. - -All forms which are not symbols are evaluated using the normal evaluation rules. - -The first argument may not be an operator such as let, et cetera. - -How many are required depends on the type of object to which the first argument -expression evaluates: of the first argument. The possibilities are: +This means that the first argument isn't a function name, but an ordinary +expression which can simply compute a function object (or, more generally, +a callable object). + +Furthermore, for those arguments of dwim which are symbols (after all +macro-expansion is performed on the arguments), the evaluation rules are +altered. For the purposes of resolving symbols to values, the function and +variable binding namespaces are considered to be merged into a single space. + +It must be noted that all arguments of dwim which, after macro expansion, are +not symbols are evaluated using the normal evaluation rules; they must +themselves be dwim forms if they are to take advantage of this feature. + +After macro expansion, the first argument of dwim may not be an operator such +as let, or the name of a macro. Prior to macroexpansion, any argument of dwim +may be a symbol macro. + +If a symbol has bindings both in the variable and function namespace in scope, +and is referenced by a dwim argument, this is conflict which is resolved +according to two rules. When nested scopes are concerned, then an inner +binding shadows an outer binding, regardless of their kind. An inner +variable binding for a symbol X shadows an outer or global function binding. +If a symbol is bound to both a function and variable in the global namespace, +then the variable binding is favored. + +How many arguments are required by the dwim operator depends on the type of +object to which the first argument expression evaluates: of the first argument. +The possibilities are: .IP "[<function> <argument>*]" Call the given the function object to the given arguments. |