ui.tools.listener.history: use FACTOR_HISTORY to optionally set histo…

…ry file

basis/ui/tools/listener/history/history.factor

@@ -1,24 +1,30 @@
 ! Copyright (C) 2009 Slava Pestov.
 ! See https://factorcode.org/license.txt for BSD license.
-USING: accessors continuations documents io io.encodings.utf8
+USING: accessors documents environment io io.encodings.utf8
 io.files io.styles kernel math math.order namespaces
-prettyprint.backend prettyprint.config sequences strings.parser ;
+prettyprint.backend prettyprint.config sequences strings.parser
+;
 IN: ui.tools.listener.history
 
 TUPLE: history document elements start index ;
 
-CONSTANT: history-file "~/.factor-history"
+: history-file ( -- path )
+    "FACTOR_HISTORY" os-env [ "~/.factor-history" ] unless* ;
 
 : read-history ( -- elements )
-    history-file file-exists? [ history-file utf8 file-lines [ unescape-string <input> ] V{ } map-as ] [ V{ } clone ] if ;
+    history-file file-exists? [
+        history-file utf8 file-lines
+        [ unescape-string <input> ] V{ } map-as
+    ] [ V{ } clone ] if ;
 
 : append-history ( history -- )
-    history-file file-exists?
-    [
+    history-file file-exists? [
         [
             history-file utf8 [
                 f string-limit? [
-                    [ elements>> ] [ start>> ] bi [ string>> f f unparse-string print ] swap each-from
+                    [ elements>> ] [ start>> ] bi
+                    [ string>> f f unparse-string print ] swap
+                    each-from
                 ] with-variable
             ] with-file-appender
         ] [ [ index>> ] keep start<< ] bi