New feature: self-load-path symbol macro.

* eval.c (self_load_path_s): New symbol variable.
(sys_load): Save, set-up and restore self-load-path
around load.
(set_get_symacro): New function.
(eval_init): Register load function using sys_load_s instead
of redundant intern.

* eval.h (set_get_symacro): Declared.

* match.c (v_load): Save, set-up and restore self-load-path
macro.

* parser.c (load_rcfile): Likewise.

* txr.c (txr_main: Set up self-load-path when opening
file.

* txr.1: Documented self-load-path.

1 files changed, 35 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index cd071bee..217a2b51 100644
--- a/txr.1
+++ b/txr.1
@@ -41399,6 +41399,41 @@ Parser error messages are directed to the
 .code *stderr*
 stream.
 
+.coNP Symbol Macro @ self-load-path
+.desc
+The
+.code self-load-path
+symbol macro expands to a string which holds the name of the file being
+loaded. This is a symbol macro rather than a variable so that it can
+be replaced during the macro-expansion process, thereby permanently embedding
+the file name into the expanded code.
+
+An expansion for
+.code self-load-path
+is established for a \*(TX or \*(TL file which is loaded from the
+command line.
+
+If the
+.code -i
+command line option is used to enter the interactive listener,
+and a file to be loaded is also specified, then the
+.code self-load-path
+macro remains bound to the name of that file.
+
+An expansion for
+.code self-load-path
+is also established by the
+.code load
+function and the
+.code @(load)
+directive, referring to the file being loaded.  When loading completes, the
+previous expansion of
+.code self-load-path
+is restored.
+
+During the processing of the profile file (see Interactive Profile File),
+the variable is bound to the name of that file.
+
 .SH* INTERACTIVE LISTENER
 
 .SS* Overview