edit a single hard-coded definition in the image

src/teliva counter.tlv
C-e  # switch to editor
C-e  # save and quit
C-x  # exit

counter.tlv now has the same logical contents, though the whitespace has
changed, and the order of keys is different.

The implementation is utterly ghastly. For one, I'm unnecessarily
interfacing with kilo through the file system.

src/kilo.c

@@ -53,6 +53,9 @@
 #include <stdarg.h>
 #include <fcntl.h>
 #include <signal.h>
+#include <stdio.h>
+
+#include "lua.h"
 
 /* Syntax highlight types */
 #define HL_NORMAL 0
@@ -1264,3 +1267,50 @@ void edit(char* filename, char* message) {
     }
     disableRawMode(STDIN_FILENO);
 }
+
+extern void teliva_get_definition(lua_State *L, const char *name);
+extern void stackDump (lua_State *L);
+extern int dostring (lua_State *L, const char *s, const char *name);
+extern char *Image_name;
+void editString(lua_State *L, char *name) {
+    /* write given definition out to tmp file */
+//?     stackDump(L);
+    teliva_get_definition(L, name);
+//?     stackDump(L);
+    char *contents = lua_tostring(L, -1);
+    int outfd = open("teliva_editbuffer", O_WRONLY|O_CREAT|O_TRUNC, 0644);
+    write(outfd, contents, strlen(contents));
+    close(outfd);
+
+    /* edit tmp file */
+    edit("teliva_editbuffer", "");
+
+    /* read contents of tmp file */
+    char new_contents[8192] = {0};
+    int infd = open("teliva_editbuffer", O_RDONLY);
+    read(infd, new_contents, 8190);  /* TODO: handle overly large file */
+    close(infd);
+
+    /* save contents back into image */
+    lua_pop(L, 1);
+    lua_pushstring(L, new_contents);
+    lua_setfield(L, -2, name);
+
+    /* save teliva_program to disk */
+    int table = lua_gettop(L);
+    FILE* fp = fopen(Image_name, "w");
+    fprintf(fp, "teliva_program = {\n");
+    for (lua_pushnil(L); lua_next(L, table) != 0; lua_pop(L, 1)) {
+      const char* key = lua_tostring(L, -2);
+      const char* value = lua_tostring(L, -1);
+      fprintf(fp, "  %s = [[", key);
+      fprintf(fp, "%s", value);
+      fprintf(fp, "]],\n");
+    }
+    fprintf(fp, "}\n");
+    fclose(fp);
+
+    /* reload binding */
+    dostring(L, new_contents, name);
+    /* TODO: handle error */
+}

src/lcurseslib.c

@@ -113,7 +113,7 @@ static int Pcolor_pair (lua_State *L)
 }
 
 
-extern void switch_to_editor(const char *message);
+extern void switch_to_editor(lua_State *L, const char *message);
 static int Pgetch (lua_State *L) {
   int c = wgetch(stdscr);
   if (c == ERR)
@@ -121,7 +121,7 @@ static int Pgetch (lua_State *L) {
   if (c == 24)  /* ctrl-x */
     exit(0);
   if (c == 5)  /* ctrl-e */
-    switch_to_editor("");
+    switch_to_editor(L, "");
   /* handle other standard menu hotkeys here */
   lua_pushinteger(L, c);
   return 1;

src/lua.c

@@ -140,7 +140,7 @@ static int dofile (lua_State *L, const char *name) {
 }
 
 
-static int dostring (lua_State *L, const char *s, const char *name) {
+int dostring (lua_State *L, const char *s, const char *name) {
   int status = luaL_loadbuffer(L, s, strlen(s), name) || docall(L, 0, 1);
   return report(L, status);
 }
@@ -244,7 +244,7 @@ static int has_extension (const char *filename, const char *extension) {
 }
 
 
-static void stackDump (lua_State *L) {
+void stackDump (lua_State *L) {
   int i;
   int top = lua_gettop(L);
   for (i = 1; i <= top; i++) {  /* repeat for each level */
@@ -274,12 +274,14 @@ static void stackDump (lua_State *L) {
 }
 
 
+char *Image_name = NULL;
 static int handle_image (lua_State *L, char **argv, int n) {
   int status;
   int narg = getargs(L, argv, n);  /* collect arguments */
   lua_setglobal(L, "arg");
   /* parse and load file contents (teliva_program table) */
-  status = luaL_loadfile(L, argv[n]);
+  Image_name = argv[n];
+  status = luaL_loadfile(L, Image_name);
   lua_insert(L, -(narg+1));
   if (status != 0) {
     return status;
@@ -306,13 +308,24 @@ static int handle_image (lua_State *L, char **argv, int n) {
 }
 
 
+/* Push the string corresponding to the definition for 'name' on the stack. */
+void teliva_get_definition(lua_State *L, const char *name) {
+  lua_getglobal(L, "teliva_program");
+  lua_getfield(L, -1, name);
+}
+
+
 /* death and rebirth */
 char *Script_name = NULL;
 char **Argv = NULL;
 extern void edit(char *filename, const char *status);
-void switch_to_editor(const char *message) {
+extern void editString(lua_State *L, char *name);
+void switch_to_editor(lua_State *L, const char *message) {
   endwin();
-  edit(Script_name, message);
+  if (Script_name)
+    edit(Script_name, message);
+  else
+    editString(L, "main");
   execv(Argv[0], Argv);
   /* never returns */
 }
@@ -323,7 +336,7 @@ static int show_error_in_editor (lua_State *L, int status) {
   if (status && !lua_isnil(L, -1)) {
     Previous_error = lua_tostring(L, -1);
     if (Previous_error == NULL) Previous_error = "(error object is not a string)";
-    switch_to_editor(Previous_error);
+    switch_to_editor(L, Previous_error);
   }
   return status;
 }