Bugfix: make self-path visible to Lisp.

The self-path variable is not bound in TXR Lisp scripts
or the command line.

* txr.c (txr_main): Set self-path to "cmdline-expr" before
command line Lisp evaluations. (For TXR pattern language
syntax invoked in a -c, it continues to be "cmdline").
Set self-path to the file name when reading a Lisp file.
Also, the legacy, undocumented *self-path* is only set
for TXR scripts, and is reverted to being a special variable,
not a global lexical.

* txr.1: Documented self-path in more detail.

1 files changed, 21 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index c2fb75ef..c8255ea2 100644
--- a/txr.1
+++ b/txr.1
@@ -33101,6 +33101,27 @@ processing; they will be processed in a later garbage collection pass.
 .coNP Variable @ self-path
 .desc
 This variable holds the invocation path name of the \*(TX program.
+The value of
+.code self-path
+when \*(TL expressions are being evaluated in command line arguments
+is the string
+.strn cmdline-expr .
+The value of
+.code self-path
+when a \*(TX query is supplied on the command line via the
+.code -c
+command line option is the string
+.strn cmdline .
+
+Note that for programs read from a file,
+.code self-path
+holds the resolved name, and not the invocation name. For instance if
+.code foo.tl
+is invoked using the name
+.codn foo ,
+whereby \*(TX infers the suffix, then
+.code self-path
+holds the suffixed name.
 
 .coNP Variable @ stdlib
 The