diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 134 |
1 files changed, 103 insertions, 31 deletions
@@ -13770,7 +13770,20 @@ if the symbol has a function binding in the global environment, otherwise it returns nil .codn nil . -.TP* "Dialect Note:" +.code mboundp +returns +.code t +if the symbol has an operator macro binding in the global environment, +otherwise +.codn nil . + +.TP* "Dialect Notes:" + +The +.code boundp +function in ANSI Common Lisp doesn't report that +global symbol macros have a binding. They are not considered +bindings. In \*(TL, they are considered bindings. The ANSI Common Lisp .code fboundp @@ -13783,12 +13796,9 @@ in Common Lisp can be obtained in \*(TL using the .cble expression. +The .code mboundp -returns -.code t -if the symbol has an operator macro binding in the global environment, -otherwise -.codn nil . +function doesn't exist in ANSI Common Lisp. .coNP Functions @, makunbound @ fmakunbound and @ mmakunbound .synb @@ -13799,24 +13809,91 @@ otherwise .desc The function .code makunbound -removes any binding for +the binding of .meta symbol -from the variable namespace of the global environment. If +from either the dynamic environment or the global symbol +macro environment. After the call to +.codn makunbound , .meta symbol -has no such binding, it does nothing. -In either case, it returns -.metn symbol . +appears to be unbound. -Both variables and symbol macros are bindings in the variable namespace. +If the +.code makunbound +call takes place in a scope in which there exists a dynamic rebinding of +.metn symbol , +the information for restoring the previous binding is not +affected by +.codn makunbound . +When that scope terminates, the previous binding will be restored. -Additionally, if +If the +.code makunbound +call takes place in a scope in which the dynamic binding for +.code symbol +is the global binding, then the global binding is removed. +When the global binding is removed, then +if .meta symbol -was previously marked as special, for instance +was previously marked as special (for instance by -.codn defvar , -this marking is removed by -.codn makunbound . +.codn defvar ) +this marking is removed. + +Otherwise if +.meta symbol +has a global symbol macro binding, that binding is removed. + +If +.meta symbol +has no apparent dynamic binding, and no global symbol macro binding, +.code makunbound +does nothing. + +In all cases, +.code makunbound +returns +.metn symbol . + +.TP* "Dialect Note:" + +The behavior of +.code makunbound +differs from its counterpart in ANSI Common Lisp. + +The +.code makunbound +function in Common Lisp only removes a value from a dynamic variable. The +dynamic variable does not cease to exist, it only ceases to have a value +(because a binding is a value). In \*(TL, the variable ceases to exist. The +binding of a variable isn't its value, it is the variable itself: the +association between a name and an abstract storage location, in some +environment. If the binding is undone, the variable disappears. + +The +.code makunbound +function in Common Lisp does not remove global symbol macros, +which are not considered to be bindings in the variable namespace. +That is to say, the Common Lisp +.code boundp +does not report true for symbol macros. +The Common Lisp +.code makunbound +also doesn't remove the special attribute from a symbol. If a variable +is introduced with +.code defvar +and then removed with +.codn makunbound , +the symbol continues to exhibit dynamic binding rather than lexical +in subsequent scopes. In \*(TL, if a global binding is removed, so +is the special attribute. + +.coNP Functions @ fmakunbound and @ mmakunbound +.synb +.mets (fmakunbound << symbol ) +.mets (mmakunbound << symbol ) +.syne +.desc The function .code fmakunbound removes any binding for @@ -13839,19 +13916,9 @@ In either case, it returns .TP* "Dialect Note:" -The behavior of these functions differs from ANSI Common Lisp. - -The -.code makunbound -function in Common Lisp only removes a value from a dynamic variable. The -dynamic variable does not cease to exist, it only ceases to have a value -(because a binding is a value). The special property from a symbol is also not -removed. In \*(TL, the variable ceases to exist. The binding -of a variable isn't its value, it is the variable itself: the association -between a name and an abstract storage location, in some environment. -If the binding is undone, the variable disappears. - -The +The behavior of +.code fmakunbound +differs from its counterpart in ANSI Common Lisp. The .code fmakunbound function in Common Lisp removes a function or macro binding, which do not coexist. @@ -43095,7 +43162,12 @@ selects the behaviors described below for version 105, but not those for 102. .IP 143 Until version 143, the .code stdlib -variable didn't include the trailing slash. +variable didn't include the trailing slash. The +.code makunbound +function semantics changed after version 143 to be more +compatible with ANSI Common Lisp. Until 143, that function removed +only the global binding, leaving the dynamic rebinding of a variable +intact. .IP 142 Until version 142, the \*(TX pattern language supported a prefix convention on data sources. Data sources beginning with the character |