Minor overhaul of history writing

Makefile.in

@@ -56,12 +56,12 @@ VPATH = $(srcdir)
 HFILES	= config.h es.h gc.h input.h prim.h print.h sigmsgs.h \
 	  stdenv.h syntax.h term.h var.h
 CFILES	= access.c closure.c conv.c dict.c eval.c except.c fd.c gc.c glob.c \
-	  glom.c input.c heredoc.c list.c main.c match.c open.c opt.c \
+	  glom.c input.c heredoc.c history.c list.c main.c match.c open.c opt.c \
 	  prim-ctl.c prim-etc.c prim-io.c prim-sys.c prim.c print.c proc.c \
 	  sigmsgs.c signal.c split.c status.c str.c syntax.c term.c token.c \
 	  tree.c util.c var.c vec.c version.c y.tab.c dump.c
 OFILES	= access.o closure.o conv.o dict.o eval.o except.o fd.o gc.o glob.o \
-	  glom.o input.o heredoc.o list.o main.o match.o open.o opt.o \
+	  glom.o input.o heredoc.o history.o list.o main.o match.o open.o opt.o \
 	  prim-ctl.o prim-etc.o prim-io.o prim-sys.o prim.o print.o proc.o \
 	  sigmsgs.o signal.o split.o status.o str.o syntax.o term.o token.o \
 	  tree.o util.o var.o vec.o version.o y.tab.o
@@ -133,6 +133,7 @@ glob.o : glob.c es.h config.h stdenv.h gc.h
 glom.o : glom.c es.h config.h stdenv.h gc.h 
 input.o : input.c es.h config.h stdenv.h input.h 
 heredoc.o : heredoc.c es.h config.h stdenv.h gc.h input.h syntax.h 
+history.o : history.c es.h config.h stdenv.h gc.h input.h 
 list.o : list.c es.h config.h stdenv.h gc.h 
 main.o : main.c es.h config.h stdenv.h 
 match.o : match.c es.h config.h stdenv.h 

doc/es.1

@@ -2559,6 +2559,22 @@ For each named
 returns the pathname, primitive, lambda, or code fragment which
 would be run if the program appeared as the first word of a command.
 .TP
+.Cr "%write-history \fIinput\fP"
+Called at the end of
+.Cr %parse
+to write the
+.I input
+to the file given in
+.Cr $history ,
+if such a file exists and can be written.
+Also appends the
+.I input
+to the in-memory history log if
+.I readline
+support is compiled in.
+(For more on this, see
+.Cr max-history-length .)
+.TP
 .Cr "%writeto \fIvar output cmd\fP"
 Runs
 .I cmd
@@ -2690,8 +2706,8 @@ apids	here	read
 close	home	run
 count	newfd	seq
 dup	openfile	split
-flatten	parse	var
-fsplit	pipe	whatis
+flatten	var	fsplit
+pipe	whatis
 .ft R
 .De
 .PP
@@ -2707,12 +2723,19 @@ batchloop	exitonfalse	isinteractive
 .De
 .PP
 The
+.Cr parse
+primitive is used to implement the
+.Cr %parse
+hook function.
+.PP
+The
 .Cr background
 primitive is used to implement the
 .Cr %background
 hook function, but does not print the process ID of the
 background process or set
 .Cr $apid .
+.PP
 The
 .Cr backquote
 primitive is used to implement the
@@ -2726,7 +2749,7 @@ The following primitives implement the similarly named settor functions:
 .ta 1.75i 3.5i
 .Ds
 .ft \*(Cf
-sethistory	setnoexport	setsignals
+setnoexport	setsignals
 .ft R
 .De
 .PP
@@ -2745,27 +2768,37 @@ writeto	%writeto
 .ft R
 .De
 .PP
-The primitive
-.Cr resetterminal
-is if
+The following primitives in particular are included if
 .I es
 is compiled with support for the
 .I readline
-library.
-It is used in the implementation of settor functions of the
-.Cr TERM
+library:
+.ta 2i
+.Ds
+.ft \*(Cf
+resetterminal	sethistory
+setmaxhistorylength	writehistory
+.ft R
+.De
+.PP
+.Cr sethistory
 and
-.Cr TERMCAP
-variables to notify the line editing packages that the terminal
-configuration has changed.
-Similarly,
 .Cr setmaxhistorylength
-is used as the settor function for the
+are used as settor functions for the
+.Cr history
+and
 .Cr max-history-length
-variable, which signals to the
-.I readline
-library how much of the history file should be read into the in-memory
-history log.
+variables.
+.Cr resetterminal
+is used in the settor functions for the
+.Cr TERM
+and
+.Cr TERMCAP
+variables.
+.Cr writehistory
+is used as the initial implementation of the
+.Cr %write-history
+function.
 .PP
 Several primitives are not directly associated with other function.
 They are:

es.h

@@ -292,11 +292,8 @@ extern Boolean streq2(const char *s, const char *t1, const char *t2);
 extern char *prompt, *prompt2;
 extern Tree *parse(char *esprompt1, char *esprompt2);
 extern Tree *parsestring(const char *str);
-extern void sethistory(char *file);
 extern Boolean isinteractive(void);
-#if HAVE_READLINE
-extern void setmaxhistorylength(int length);
-#endif
+extern Boolean isfromfd(void);
 extern void initgetenv(void);
 extern void initinput(void);
 extern void resetparser(void);
@@ -316,6 +313,21 @@ extern Boolean resetterminal;
 #endif
 
 
+/* history.c */
+#if HAVE_READLINE
+extern void inithistory(void);
+
+extern void sethistory(char *file);
+extern void loghistory(char *cmd);
+extern void setmaxhistorylength(int length);
+extern void checkreloadhistory(void);
+#endif
+
+extern void newhistbuffer(void);
+extern void addhistbuffer(char c);
+extern char *dumphistbuffer(void);
+
+
 /* opt.c */
 
 extern void esoptbegin(List *list, const char *caller, const char *usage, Boolean throws);

heredoc.c

@@ -44,7 +44,6 @@ extern Tree *snarfheredoc(const char *eof, Boolean quoted) {
 		return NULL;
 	}
 	ignoreeof = TRUE;
-	disablehistory = TRUE;
 
 	for (tree = NULL, tailp = &tree, buf = openbuffer(0);;) {
 		int c;
@@ -65,7 +64,6 @@ extern Tree *snarfheredoc(const char *eof, Boolean quoted) {
 				yyerror("incomplete here document");
 				freebuffer(buf);
 				ignoreeof = FALSE;
-				disablehistory = FALSE;
 				return NULL;
 			}
 			if (c == '$' && !quoted && (c = GETC()) != '$') {
@@ -81,7 +79,6 @@ extern Tree *snarfheredoc(const char *eof, Boolean quoted) {
 				if (var == NULL) {
 					freebuffer(buf);
 					ignoreeof = FALSE;
-					disablehistory = FALSE;
 					return NULL;
 				}
 				*tailp = treecons(var, NULL);
@@ -96,7 +93,6 @@ extern Tree *snarfheredoc(const char *eof, Boolean quoted) {
 	}
 
 	ignoreeof = FALSE;
-	disablehistory = FALSE;
 	return tree->CDR == NULL ? tree->CAR : tree;
 }
 
@@ -146,5 +142,4 @@ extern Boolean queueheredoc(Tree *t) {
 
 extern void emptyherequeue(void) {
 	hereq = NULL;
-	disablehistory = FALSE;
 }

history.c

@@ -0,0 +1,134 @@
+/* history.c -- control the history file ($Revision: 1.1.1.1 $) */
+
+#include "es.h"
+#include "gc.h"
+#include "input.h"
+
+
+/*
+ * constants
+ */
+
+#define	BUFSIZE		((size_t) 4096)		/* buffer size to fill reads into */
+
+
+/*
+ * globals
+ */
+
+static Buffer *histbuffer = NULL;
+
+#if HAVE_READLINE
+#include <readline/history.h>
+
+Boolean reloadhistory = FALSE;
+static char *history;
+
+#if 0
+/* These split history file entries by timestamp, which allows readline to pick up
+ * multi-line commands correctly across process boundaries.  Disabled by default,
+ * because it leaves the history file itself kind of ugly. */
+static int history_write_timestamps = 1;
+static char history_comment_char = '#';
+#endif
+#endif
+
+
+/*
+ * histbuffer -- build the history line during input and dump it as a gc-string
+ */
+
+
+extern void newhistbuffer() {
+	assert(histbuffer == NULL);
+	histbuffer = openbuffer(BUFSIZE);
+}
+
+extern void addhistbuffer(char c) {
+	if (histbuffer == NULL)
+		return;
+	histbuffer = bufputc(histbuffer, c);
+}
+
+extern char *dumphistbuffer() {
+	char *s;
+        size_t len;
+	assert(histbuffer != NULL);
+
+	s = sealcountedbuffer(histbuffer);
+	histbuffer = NULL;
+
+	len = strlen(s);
+	if (len > 0 && s[len - 1] == '\n')
+		s[len - 1] = '\0';
+	return s;
+}
+
+
+/*
+ * history file
+ */
+
+#if HAVE_READLINE
+extern void setmaxhistorylength(int len) {
+	static int currenthistlen = -1; /* unlimited */
+	if (len != currenthistlen) {
+		switch (len) {
+		case -1:
+			unstifle_history();
+			break;
+		case 0:
+			clear_history();
+			FALLTHROUGH;
+		default:
+			stifle_history(len);
+		}
+		currenthistlen = len;
+	}
+}
+
+extern void loghistory(char *cmd) {
+	int err;
+	if (cmd == NULL)
+		return;
+	add_history(cmd);
+	if (history == NULL)
+		return;
+
+	if ((err = append_history(1, history))) {
+		eprint("history(%s): %s\n", history, esstrerror(err));
+		vardef("history", NULL, NULL);
+	}
+}
+
+static void reload_history(void) {
+	/* Attempt to populate readline history with new history file. */
+	if (history != NULL)
+		read_history(history);
+	using_history();
+
+	reloadhistory = FALSE;
+}
+
+extern void sethistory(char *file) {
+	if (reloadhistory)
+		reload_history();
+	reloadhistory = TRUE;
+	history = file;
+}
+
+extern void checkreloadhistory(void) {
+	if (reloadhistory)
+		reload_history();
+}
+
+/*
+ * initialization
+ */
+
+/* inithistory -- called at dawn of time from main() */
+extern void inithistory(void) {
+	/* declare the global roots */
+	globalroot(&history);		/* history file */
+}
+#endif