From 9361473290d317186768bd9d709ae76adf9d85b8 Mon Sep 17 00:00:00 2001 From: Kaz Kylheku Date: Fri, 29 Dec 2017 16:52:52 -0800 Subject: read, iread: source location recording now conditional. Recording of source location info incurs a time and space penalty. We don't want to impose this on programs which are just reading large amounts of Lisp data that isn't code. * eval.c (eval_init): Register lisp-parse and read functions to the newly introduced nread function rather than lisp_parse. lisp_parse continues to record source location info unconditionally. * parser.c (rec_source_loc_s): New symbol variable. (parser_common_init): Set the new member of the parser structure, rec_source_loc, according to the current value of the special var *rec-source-loc*. (lisp_parse_impl): New second argument, rlcp_p. If true, it overrides the rec_source_loc member of the parser structure to true. (lisp_parse): Pass true argument to rlcp_p parameter of lisp_parse_impl, so parsing via lisp_parse always records source loc info. (nread): New function. (iread): Pass true argument to rlcp_p parameter of lisp_parse_impl, so *rec-source-loc* controls whether source location info is recorded. (parse_init): Initilize rec_source_loc_s symbol variable, and register the *rec-source-loc* special var. * parser.h (struct parser): New member, rec_source_loc. (rec_source_loc_s, nread): Declared. * parser.y (rlcp_parser): New static function. Like rlcp but does nothing if parser->rec_source_loc is false. (rlc): New macro. (grammar): Replace rlcp uses with rlc, which expands to a call to rlcp_parser. (rlrec): Do nothing if source loc recording is not enabled in the parser. (make_expr, uref_helper): Replace rlcp with rlc. This is possible because these functions have a parser local variable that the macro expansion can refer to. (parse_once): Override rec_source_loc in the parser to 1, so that source loc info is always recorded when parsing is invoked through this function. * txr.1: Documented *rec-source-loc* and added text under read and iread. --- txr.1 | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'txr.1') diff --git a/txr.1 b/txr.1 index f948f155..a90b5a8a 100644 --- a/txr.1 +++ b/txr.1 @@ -43888,6 +43888,16 @@ possibility that the expression will be further extended by means of the dot or dotdot operators. An explicit end-of-input signal must be given from the terminal to terminate the expression. +The special variable +.code *rec-source-loc* +controls whether these functions record source location info similarly to +.codn load . +Note: if these functions are used to scan data which is evaluated as Lisp code, +it may be useful to set +.code *rec-source-loc* +true in order to obtain better diagnostics. However, source location recording +incurs a performance and storage penalty. + .coNP Function @ record-adapter .synb .mets (record-adapter < regex >> [ stream <> [ include-match ]]) @@ -54616,6 +54626,31 @@ has location info, the expander propagates that info to that form's expansion. In some situations, it is useful for a macro or other code transformer to perform this action explicitly. +.coNP Special variable *rec-source-loc* +.desc +The Boolean special variable +.code *rec-source-loc* +controls whether the +.code read +and +.code iread +functions record source location info. The variable is +.code nil +by default, so that these functions do not record source location info. +If it is true, then these functions record source location info. + +Regardless of the value of this variable, source location info is +recorded for Lisp forms which are read from files or streams under the +.code load +function or specified on the \*(TX command line. Source location +info is also always recorded when reading the \*(TX pattern language syntax. + +Note: recording and propagating location info incurs a memory and performance +penalty. The individual cons cells and certain other literal objects in the +structure which emerges from the parser are associated with source location +info via a global weak hash table. + + .coNP Function @ macro-ancestor .synb .mets (macro-ancestor << form ) -- cgit v1.2.3