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Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 20 |
1 files changed, 20 insertions, 0 deletions
@@ -39715,6 +39715,21 @@ and .codn "(d e)" . These compounds express nested macro parameter lists. +Starting in \*(TX 285, the symbol +.code t +can be used in a macro parameter list in place of a parameter name. +This indicates that an object is expected at that position in the +corresponding structure, but no variable will be bound. +For completeness, the +.code t +symbol may also be used for a presence-indicating variable. +When the name of an optional parameter is specified as +.codn t , +and the corresponding structure is missing, the +.meta init-val +expression, if present, is still evaluated under the same +circumstances as it would if a variable were present. + Nested macro parameter lists recursively match the corresponding structure in the argument object. For instance if a simple argument would capture the structure @@ -39846,6 +39861,11 @@ and binds to the entire .code tree-bind form. +ANSI CL doesn't support the convention that the +.code t +symbol may appear instead of a parameter symbol to +suppress the binding of a variable. + .NP* The Macro Expansion Process The following description omits the treatment of top-level forms by |