diff options
| -rw-r--r-- | ChangeLog | 12 | ||||
| -rw-r--r-- | eval.c | 9 | ||||
| -rw-r--r-- | txr.1 | 35 |
3 files changed, 44 insertions, 12 deletions
@@ -1,5 +1,17 @@ 2014-02-22 Kaz Kylheku <kaz@kylheku.com> + * eval.c (symbol_function): Retrieve the global macro binding if the + function lookup fails, and if that fails, retrieve the special + operator binding. + (fboundp): Report t if there is a global macro binding. + + * txr.1: Use "global" rather than "toplevel". Added note that + the fun operator doesn't see macro bindings. Documented that + symbol-function and fboundp see global macro bindings, + and that symbol-function can retrieve a special operator binding. + +2014-02-22 Kaz Kylheku <kaz@kylheku.com> + * eval.c (prinl, pprinl): New functions. (eval_init): Registered as intrinsics. @@ -2522,7 +2522,10 @@ static val symbol_value(val sym) static val symbol_function(val sym) { - return cdr(lookup_fun(nil, sym)); + uses_or2; + return or2(cdr(or2(lookup_fun(nil, sym), + lookup_mac(nil, sym))), + gethash(op_table, sym)); } static val boundp(val sym) @@ -2532,8 +2535,8 @@ static val boundp(val sym) static val fboundp(val sym) { - return if3(lookup_fun(nil, sym), t, - if3(gethash(op_table, sym), t, nil)); + return if2(lookup_fun(nil, sym) || lookup_mac(nil, sym) || + gethash(op_table, sym), t); } static val rangev_func(val env, val lcons) @@ -6189,10 +6189,14 @@ Syntax: .TP Description: The fun operator retrieves the function object corresponding to a named -function. -. The <function-name> is a symbol denoting a named function: a built in +function in the current lexical environment. + +The <function-name> is a symbol denoting a named function: a built in function, or one defined by defun. +Note: the fun operator does not see macro bindings. It is possible to +retrieve a global macro expander using symbol-function. + .TP Dialect Note: A lambda expression is not a function name in TXR Lisp. The @@ -6209,20 +6213,33 @@ Syntax: .TP Description: -The symbol-function retrieves the value of the toplevel function binding of the +The symbol-function retrieves the value of the global function binding of the given symbol if it has one: that is, the function object tied to the symbol. If -the symbol has no toplevel function binding, the value nil is returned. +the symbol has no global function binding, then the value of the global macro +binding is returned. If that doesn't exist, then the value of a global special +operator binding is returned, and if that doesn't exist, then nil is returned. -The symbol-value retrives the value of a toplevel variable, if it exists, +The symbol-value retrives the value of a global variable, if it exists, otherwise nil. +Note: a function binding is a function, but a macro or special operator binding +binding isn't. The value of a macro binding is a list of the following form: + + (#<environment object> <macro-parameter-list> <body-form>*) + +The value of a special operator binding is a "C pointer" object, whose +printed representation looks like: + + #<cptr: 808be4f> + +These details may change in future version of TXR. + .TP Dialect note: Forms which call symbol-function or symbol-value are currently not an assignable place. Only the defun operator defines functions, and the set -operator modifies variables. There is no way to modify a toplevel variable that -is shadowed by a lexical variable. +operator modifies variables. .SS Functions boundp and fboundp @@ -6235,10 +6252,10 @@ Syntax: .TP Description: -boundp returns t if the symbol has a variable binding in the toplevel +boundp returns t if the symbol has a variable binding in the global environment, otherwise nil. -Foundp returns t if the symbol has a function binding in the toplevel +Foundp returns t if the symbol has a function or macro binding in the global environment, or if it is an operator, otherwise nil. .SS Function func-get-form |