core: add syntax highlighting in evaluation of expressions, add option weechat.color.eval_syntax_colors (issue #2042)

Syntax highlighting (raw string without evaluation): `${raw_hl:xxx}`
Syntax highlighting: `${hl:xxx}`

4 files changed, 219 insertions, 11 deletions

diff --git a/src/core/wee-config.c b/src/core/wee-config.c
index ebf058958..0b380c669 100644
--- a/src/core/wee-config.c
+++ b/src/core/wee-config.c
@@ -269,6 +269,7 @@ struct t_config_option *config_color_chat_value = NULL;
 struct t_config_option *config_color_chat_value_null = NULL;
 struct t_config_option *config_color_emphasized = NULL;
 struct t_config_option *config_color_emphasized_bg = NULL;
+struct t_config_option *config_color_eval_syntax_colors = NULL;
 struct t_config_option *config_color_input_actions = NULL;
 struct t_config_option *config_color_input_text_not_found = NULL;
 struct t_config_option *config_color_item_away = NULL;
@@ -364,6 +365,8 @@ int config_word_chars_input_count = 0;
 char **config_nick_colors = NULL;
 int config_num_nick_colors = 0;
 struct t_hashtable *config_hashtable_nick_color_force = NULL;
+char **config_eval_syntax_colors = NULL;
+int config_num_eval_syntax_colors = 0;
 char *config_item_time_evaluated = NULL;
 char *config_buffer_time_same_evaluated = NULL;
 struct t_hashtable *config_hashtable_completion_partial_templates = NULL;
@@ -823,6 +826,31 @@ config_change_look_nick_color_force (const void *pointer, void *data,
 }
 
 /*
+ * Sets eval syntax highlighting colors using option
+ * "weechat.color.eval_syntax_colors".
+ */
+
+void
+config_set_eval_syntax_colors ()
+{
+    if (config_eval_syntax_colors)
+    {
+        string_free_split (config_eval_syntax_colors);
+        config_eval_syntax_colors = NULL;
+        config_num_eval_syntax_colors = 0;
+    }
+
+    config_eval_syntax_colors = string_split (
+        CONFIG_STRING(config_color_eval_syntax_colors),
+        ",",
+        NULL,
+        WEECHAT_STRING_SPLIT_STRIP_LEFT
+        | WEECHAT_STRING_SPLIT_STRIP_RIGHT
+        | WEECHAT_STRING_SPLIT_COLLAPSE_SEPS,
+        0, &config_num_eval_syntax_colors);
+}
+
+/*
  * Callback for changes on options "weechat.look.nick_prefix" and
  * "weechat.look.nick_suffix".
  */
@@ -1296,6 +1324,23 @@ config_change_nick_colors (const void *pointer, void *data,
 }
 
 /*
+ * Callback for changes on option "weechat.color.eval_syntax_colors".
+ */
+
+void
+config_change_eval_syntax_colors (const void *pointer, void *data,
+                                  struct t_config_option *option)
+{
+    /* make C compiler happy */
+    (void) pointer;
+    (void) data;
+    (void) option;
+
+    config_set_eval_syntax_colors ();
+    gui_color_buffer_display ();
+}
+
+/*
  * Callback for changes on option
  * "weechat.completion.partial_completion_templates".
  */
@@ -1516,7 +1561,9 @@ config_weechat_init_after_read ()
     /* apply filters on all buffers */
     gui_filter_all_buffers (NULL);
 
+    config_set_nick_colors ();
     config_change_look_nick_color_force (NULL, NULL, NULL);
+    config_set_eval_syntax_colors ();
 }
 
 /*
@@ -4611,6 +4658,21 @@ config_weechat_init_options ()
             NULL, NULL, NULL,
             &config_change_color, NULL, NULL,
             NULL, NULL, NULL);
+        /* eval syntax highlighting colors (for "${raw_hl:xxx}" and "${hl:xxx}") */
+        config_color_eval_syntax_colors = config_file_new_option (
+            weechat_config_file, weechat_config_section_color,
+            "eval_syntax_colors", "string",
+            /* TRANSLATORS: please do not translate "lightred:blue" */
+            N_("text color for syntax highlighting in evaluated strings, "
+               "with \"${raw_hl:...}\" and \"${hl:...}\" (comma separated "
+               "list of colors, background is allowed with format: \"fg:bg\", "
+               "for example: \"lightred:blue\")"),
+            NULL, 0, 0,
+            "green,lightred,lightblue,lightmagenta,yellow,cyan",
+            NULL, 0,
+            NULL, NULL, NULL,
+            &config_change_eval_syntax_colors, NULL, NULL,
+            NULL, NULL, NULL);
         /* input bar */
         config_color_input_actions = config_file_new_option (
             weechat_config_file, weechat_config_section_color,
@@ -4654,7 +4716,7 @@ config_weechat_init_options ()
             NULL, NULL, NULL,
             &config_change_color, NULL, NULL,
             NULL, NULL, NULL);
-        /* general color settings */
+        /* separator */
         config_color_separator = config_file_new_option (
             weechat_config_file, weechat_config_section_color,
             "separator", "color",
@@ -5374,6 +5436,13 @@ config_weechat_free ()
         config_num_nick_colors = 0;
     }
 
+    if (config_eval_syntax_colors)
+    {
+        string_free_split (config_eval_syntax_colors);
+        config_eval_syntax_colors = NULL;
+        config_num_eval_syntax_colors = 0;
+    }
+
     if (config_hashtable_nick_color_force)
     {
         hashtable_free (config_hashtable_nick_color_force);
diff --git a/src/core/wee-config.h b/src/core/wee-config.h
index a191505f1..9f38bac6b 100644
--- a/src/core/wee-config.h
+++ b/src/core/wee-config.h
@@ -321,6 +321,7 @@ extern struct t_config_option *config_color_chat_value;
 extern struct t_config_option *config_color_chat_value_null;
 extern struct t_config_option *config_color_emphasized;
 extern struct t_config_option *config_color_emphasized_bg;
+extern struct t_config_option *config_color_eval_syntax_colors;
 extern struct t_config_option *config_color_input_actions;
 extern struct t_config_option *config_color_input_text_not_found;
 extern struct t_config_option *config_color_item_away;
@@ -400,6 +401,8 @@ extern int config_word_chars_input_count;
 extern char **config_nick_colors;
 extern int config_num_nick_colors;
 extern struct t_hashtable *config_hashtable_nick_color_force;
+extern char **config_eval_syntax_colors;
+extern int config_num_eval_syntax_colors;
 extern char *config_buffer_time_same_evaluated;
 extern struct t_hashtable *config_hashtable_completion_partial_templates;
 
diff --git a/src/core/wee-eval.c b/src/core/wee-eval.c
index c2370b504..4d8c0e7da 100644
--- a/src/core/wee-eval.c
+++ b/src/core/wee-eval.c
@@ -32,7 +32,7 @@
 #include "weechat.h"
 #include "wee-eval.h"
 #include "wee-calc.h"
-#include "wee-config-file.h"
+#include "wee-config.h"
 #include "wee-hashtable.h"
 #include "wee-hdata.h"
 #include "wee-hook.h"
@@ -1465,12 +1465,121 @@ end:
 }
 
 /*
+ * Returns text with syntax highlighting (using markers, to be replaced by
+ * colors later).
+ *
+ * Note: result must be freed after use.
+ */
+
+char *
+eval_syntax_highlight_add_markers (const char *text,
+                                   struct t_eval_context *eval_context)
+{
+    char **value;
+
+    value = string_dyn_alloc (128);
+    if (!value)
+        return NULL;
+
+    string_dyn_concat (value, EVAL_SYNTAX_HL_INC, -1);
+    string_dyn_concat (value, eval_context->prefix, -1);
+    if (text)
+        string_dyn_concat (value, text, -1);
+    string_dyn_concat (value, eval_context->suffix, -1);
+    string_dyn_concat (value, EVAL_SYNTAX_HL_DEC, -1);
+
+    return string_dyn_free (value, 0);
+}
+
+/*
+ * Replaces raw highlight markers with color codes defined in option
+ * weechat.color.eval_syntax_colors.
+ *
+ * Note: result must be freed after use.
+ */
+
+char *
+eval_syntax_highlight_colorize (const char *value)
+{
+    const char *ptr_value;
+    char **result, *pos;
+    int color;
+
+    if (!value)
+        return NULL;
+
+    result = string_dyn_alloc (128);
+    if (!result)
+        return NULL;
+
+    color = -1;
+    ptr_value = value;
+    while (ptr_value && ptr_value[0])
+    {
+        pos = strstr (ptr_value, EVAL_SYNTAX_HL_MARKER);
+        if (!pos)
+        {
+            string_dyn_concat (result, ptr_value, -1);
+            break;
+        }
+        string_dyn_concat (result, ptr_value, pos - ptr_value);
+        ptr_value = pos + strlen (EVAL_SYNTAX_HL_MARKER);
+        if (config_num_eval_syntax_colors > 0)
+        {
+            if (ptr_value[0] == '+')
+                color++;
+            else if (ptr_value[0] == '-')
+                color--;
+        }
+        ptr_value++;
+        if (config_num_eval_syntax_colors > 0)
+        {
+            string_dyn_concat (
+                result,
+                gui_color_get_custom (
+                    (color >= 0) ?
+                    config_eval_syntax_colors[color % config_num_eval_syntax_colors] :
+                    "reset"),
+                -1);
+        }
+    }
+
+    return string_dyn_free (result, 0);
+}
+
+/*
+ * Adds syntax highlighting in text.
+ *
+ * Note: result must be freed after use.
+ */
+
+char *
+eval_syntax_highlight (const char *text, struct t_eval_context *eval_context)
+{
+    char *value, *value2;
+
+    eval_context->syntax_highlight++;
+
+    value = eval_replace_vars (text, eval_context);
+    value2 = eval_syntax_highlight_colorize (value);
+    if (value)
+        free (value);
+
+    eval_context->syntax_highlight--;
+
+    return value2;
+}
+
+/*
  * Replaces variables, which can be, by order of priority:
+ *  - the string itself without evaluation but with syntax highlighting
+ *    (format: raw_hl:xxx)
  *  - the string itself without evaluation (format: raw:xxx)
+ *  - a string with syntax highlighting (format: hl:xxx)
  *  - a variable from hashtable "user_vars" or "extra_vars"
  *  - a WeeChat home directory, one of: "weechat_config_dir",
  *    "weechat_data_dir", "weechat_cache_dir", "weechat_runtime_dir"
- *  - a string to evaluate (format: eval:xxx)
+ *  - an evaluated string (format: eval:xxx)
  *  - a condition to evaluate (format: eval_cond:xxx)
  *  - a string with escaped chars (format: esc:xxx or \xxx)
  *  - a string with a range of chars (format: chars:range)
@@ -1531,6 +1640,16 @@ eval_replace_vars_cb (void *data, const char *text)
 
     EVAL_DEBUG_MSG(1, "eval_replace_vars_cb(\"%s\")", text);
 
+    if (eval_context->syntax_highlight)
+        return eval_syntax_highlight_add_markers (text, eval_context);
+
+    /* raw text (no evaluation at all), with syntax highlighting */
+    if (strncmp (text, "raw_hl:", 7) == 0)
+    {
+        value = eval_syntax_highlight (text + 7, eval_context);
+        goto end;
+    }
+
     /* raw text (no evaluation at all) */
     if (strncmp (text, "raw:", 4) == 0)
     {
@@ -1538,6 +1657,13 @@ eval_replace_vars_cb (void *data, const char *text)
         goto end;
     }
 
+    /* syntax highlighting */
+    if (strncmp (text, "hl:", 3) == 0)
+    {
+        value = eval_syntax_highlight (text + 3, eval_context);
+        goto end;
+    }
+
     /* variable in hashtable "user_vars" or "extra_vars" */
     ptr_value = hashtable_get (eval_context->user_vars, text);
     if (ptr_value)
@@ -1891,7 +2017,8 @@ end:
 char *
 eval_replace_vars (const char *expr, struct t_eval_context *eval_context)
 {
-    const char *no_replace_prefix_list[] = { "if:", "raw:", NULL };
+    const char *no_replace_prefix_list_std[] = { "if:", "raw:", "raw_hl:", NULL };
+    const char *no_replace_prefix_list_col[] = { "raw:", "raw_hl:", NULL };
     char *result;
     int debug_id;
 
@@ -1901,13 +2028,15 @@ eval_replace_vars (const char *expr, struct t_eval_context *eval_context)
 
     if (eval_context->recursion_count < EVAL_RECURSION_MAX)
     {
-        result = string_replace_with_callback (expr,
-                                               eval_context->prefix,
-                                               eval_context->suffix,
-                                               no_replace_prefix_list,
-                                               &eval_replace_vars_cb,
-                                               eval_context,
-                                               NULL);
+        result = string_replace_with_callback (
+            expr,
+            eval_context->prefix,
+            eval_context->suffix,
+            (eval_context->syntax_highlight) ?
+            no_replace_prefix_list_col : no_replace_prefix_list_std,
+            &eval_replace_vars_cb,
+            eval_context,
+            NULL);
     }
     else
     {
@@ -2542,6 +2671,7 @@ eval_expression (const char *expr, struct t_hashtable *pointers,
     eval_context->regex = NULL;
     eval_context->regex_replacement_index = 1;
     eval_context->recursion_count = 0;
+    eval_context->syntax_highlight = 0;
     eval_context->debug_level = 0;
     eval_context->debug_depth = 0;
     eval_context->debug_id = 0;
diff --git a/src/core/wee-eval.h b/src/core/wee-eval.h
index b703c03ed..6f00c4620 100644
--- a/src/core/wee-eval.h
+++ b/src/core/wee-eval.h
@@ -37,6 +37,10 @@
 #define EVAL_RANGE_ALPHA    EVAL_RANGE_LOWER EVAL_RANGE_UPPER
 #define EVAL_RANGE_ALNUM    EVAL_RANGE_ALPHA EVAL_RANGE_DIGIT
 
+#define EVAL_SYNTAX_HL_MARKER  "\xef\xbf\xbf\xef\xbf\xbf"
+#define EVAL_SYNTAX_HL_INC     (EVAL_SYNTAX_HL_MARKER "+")
+#define EVAL_SYNTAX_HL_DEC     (EVAL_SYNTAX_HL_MARKER "-")
+
 struct t_hashtable;
 
 enum t_eval_logical_op
@@ -89,6 +93,8 @@ struct t_eval_context
     struct t_eval_regex *regex;        /* in case of replace with regex     */
     int regex_replacement_index;       /* replacement index (≥ 1)           */
     int recursion_count;               /* to prevent infinite recursion     */
+    int syntax_highlight;              /* syntax highlight: ${raw_hl:...}   */
+                                       /* or ${hl:...}                      */
     int debug_level;                   /* 0: no debug, 1: debug, 2: extra   */
     int debug_depth;                   /* used for debug indentation        */
     int debug_id;                      /* operation id in debug output      */