Task #11442. Access to environment variables.

* lib.c (env_list): New static variable.
(env): New function.
(match): Declaration of nonexistent function removed.
(obj_init): New variable gc-protected.

* lib.h (env): Declared.

* match.c (env_k): New symbol variable.
(v_next): Implemented :env.

* txr.1: @(next :env) described.

1 files changed, 6 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index edf0bbd0..1523f3a4 100644
--- a/txr.1
+++ b/txr.1
@@ -1114,6 +1114,7 @@ with, or without arguments:
   @(next SOURCE)
   @(next SOURCE :nothrow)
   @(next :args)
+  @(next :env)
   @(next :list EXPR)
   @(next :string EXPR)
 
@@ -1151,6 +1152,11 @@ open the input source named by that argument. If the very first directive of a q
 avoids opening the first input source, but it does open the input source for
 any other directive, even one which does not consume any data.
 
+The variant @(next :env) means that the list of process enviornment variables
+is treated as a source of data. It looks like a text file stream
+consisting of lines of the form "name=value".  If this feature is not available
+on a given platform, an exception is thrown.
+
 The syntax @(next :list EXPR) treats the expression as a source of
 text. The value of the expression is flattened to a list in a way similar
 to the @(flatten) directive.  The resulting list is treated as if it were the