Highlight quote marks & brackets

src/guiguts/application.py

@@ -21,6 +21,7 @@
     highlight_single_quotes,
     highlight_double_quotes,
     remove_highlights,
+    highlight_quotbrac_callback,
 )
 from guiguts.maintext import maintext
 from guiguts.mainwindow import (
@@ -412,6 +413,10 @@ def initialize_preferences(self) -> None:
                 str(DEFAULT_SCANNOS_DIR.joinpath(DEFAULT_STEALTH_SCANNOS)),
             ],
         )
+        preferences.set_default(PrefKey.HIGHLIGHT_QUOTBRAC, False)
+        preferences.set_callback(
+            PrefKey.HIGHLIGHT_QUOTBRAC, highlight_quotbrac_callback
+        )
 
         # Check all preferences have a default
         for pref_key in PrefKey:
@@ -582,6 +587,10 @@ def init_search_menu(self) -> None:
             "Highlight ~Double Quotes in Selection",
             highlight_double_quotes,
         )
+        menu_search.add_checkbox(
+            "Highlight S~urrounding Quotes & Brackets",
+            root().highlight_quotbrac,
+        )
         menu_search.add_button(
             "~Remove Highlights",
             remove_highlights,

src/guiguts/highlight.py

@@ -12,6 +12,13 @@ class HighlightTag(StrEnum):
 
     QUOTEMARK = auto()
     SPOTLIGHT = auto()
+    PAREN = auto()
+    CURLY_BRACKET = auto()
+    SQUARE_BRACKET = auto()
+    STRAIGHT_DOUBLE_QUOTE = auto()
+    CURLY_DOUBLE_QUOTE = auto()
+    STRAIGHT_SINGLE_QUOTE = auto()
+    CURLY_SINGLE_QUOTE = auto()
 
 
 class HighlightColors:
@@ -39,6 +46,48 @@ class HighlightColors:
         "Default": {"bg": "orange", "fg": "black"},
     }
 
+    PAREN = {
+        "Light": {"bg": "violet", "fg": "white"},
+        "Dark": {"bg": "violet", "fg": "white"},
+        "Default": {"bg": "violet", "fg": "white"},
+    }
+
+    CURLY_BRACKET = {
+        "Light": {"bg": "blue", "fg": "white"},
+        "Dark": {"bg": "blue", "fg": "white"},
+        "Default": {"bg": "blue", "fg": "white"},
+    }
+
+    SQUARE_BRACKET = {
+        "Light": {"bg": "purple", "fg": "white"},
+        "Dark": {"bg": "purple", "fg": "white"},
+        "Default": {"bg": "purple", "fg": "white"},
+    }
+
+    STRAIGHT_DOUBLE_QUOTE = {
+        "Light": {"bg": "green", "fg": "white"},
+        "Dark": {"bg": "green", "fg": "white"},
+        "Default": {"bg": "green", "fg": "white"},
+    }
+
+    CURLY_DOUBLE_QUOTE = {
+        "Light": {"bg": "limegreen", "fg": "white"},
+        "Dark": {"bg": "limegreen", "fg": "white"},
+        "Default": {"bg": "limegreen", "fg": "white"},
+    }
+
+    STRAIGHT_SINGLE_QUOTE = {
+        "Light": {"bg": "grey", "fg": "white"},
+        "Dark": {"bg": "grey", "fg": "white"},
+        "Default": {"bg": "grey", "fg": "white"},
+    }
+
+    CURLY_SINGLE_QUOTE = {
+        "Light": {"bg": "dodgerblue", "fg": "white"},
+        "Dark": {"bg": "dodgerblue", "fg": "white"},
+        "Default": {"bg": "dodgerblue", "fg": "white"},
+    }
+
 
 def highlight_selection(
     pat: str,
@@ -79,25 +128,13 @@ def highlight_quotemarks(pat: str) -> None:
 
 
 def highlight_single_quotes() -> None:
-    """Highlight single quotes in current selection.
-
-    ' APOSTROPHE
-    ‘’ {LEFT, RIGHT} SINGLE QUOTATION MARK
-    ‹› SINGLE {LEFT, RIGHT}-POINTING ANGLE QUOTATION MARK
-    ‛‚ SINGLE {HIGH-REVERSED-9, LOW-9} QUOTATION MARK
-    """
-    highlight_quotemarks("['‘’‹›‛‚]")
+    """Highlight single quotes (straight or curly) in current selection."""
+    highlight_quotemarks("['‘’]")
 
 
 def highlight_double_quotes() -> None:
-    """Highlight double quotes in current selection.
-
-    " QUOTATION MARK
-    “” {LEFT, RIGHT} DOUBLE QUOTATION MARK
-    «» {LEFT, RIGHT}-POINTING DOUBLE ANGLE QUOTATION MARK
-    ‟„ DOUBLE {HIGH-REVERSED-9, LOW-9} QUOTATION MARK
-    """
-    highlight_quotemarks('["“”«»‟„]')
+    """Highlight double quotes (straight or curly) in current selection."""
+    highlight_quotemarks('["“”]')
 
 
 def spotlight_range(spot_range: IndexRange) -> None:
@@ -133,3 +170,266 @@ def _highlight_configure_tag(
         background=tag_colors[theme]["bg"],
         foreground=tag_colors[theme]["fg"],
     )
+
+
+def highlight_single_pair_bracketing_cursor(
+    startchar: str,
+    endchar: str,
+    tag_name: str,
+    tag_colors: dict[str, dict[str, str]],
+    *,
+    charpair: str = "",
+) -> None:
+    """
+    Search for a pair of matching characters that bracket the cursor and tag
+    them with the given tagname. If charpair is not specified, a default regex
+    of f"[{startchar}{endchar}]" will be used.
+
+    Args:
+        startchar: opening char of pair (e.g. '(')
+        endchar: closing chair of pair (e.g. ')')
+        tag_name: name of tag for highlighting (class HighlightTag)
+        tag_colors: dict of color information (class HighlightColors)
+        charpair: optional regex override for matching the pair (e.g. '[][]')
+    """
+    maintext().tag_delete(tag_name)
+    _highlight_configure_tag(tag_name, tag_colors)
+    cursor = maintext().get_insert_index().index()
+
+    (top_index, bot_index) = get_screen_window_coordinates()
+
+    # search backward for the startchar
+    startindex = search_for_base_character_in_pair(
+        top_index,
+        cursor,
+        bot_index,
+        startchar,
+        endchar,
+        charpair=charpair,
+        backwards=True,
+    )
+    if not startindex:
+        return
+
+    # search forward for the endchar
+    endindex = search_for_base_character_in_pair(
+        top_index, cursor, bot_index, startchar, endchar, charpair=charpair
+    )
+
+    if not (startindex and endindex):
+        return
+
+    maintext().tag_add(tag_name, startindex, maintext().index(f"{startindex}+1c"))
+    maintext().tag_add(tag_name, endindex, maintext().index(f"{endindex}+1c"))
+
+
+def get_screen_window_coordinates() -> tuple[str, str]:
+    """
+    Find start and end coordinates for viewport (with a margin of
+    offscreen text added for padding).
+    """
+    # A magic number cribbed from Tk.pm's TextEdit.pm.
+    # This is how many rows to explore beyond the visible viewport.
+    offscreen_rows = 80
+
+    (top_frac, bot_frac) = maintext().focus_widget().yview()
+    end_index = maintext().rowcol("end")
+
+    # Don't try to go beyond the boundaries of the document.
+    #
+    # {top,bot}_frac contain a fractional number representing a percentage into
+    # the document; do some math to calculate what the top or bottom row in the
+    # viewport should be, then use min/max to make sure that value isn't less
+    # than 0 or more than the total row count.
+    top_line = max(int((top_frac * end_index.row) - offscreen_rows), 0)
+    bot_line = min(int((bot_frac * end_index.row) + offscreen_rows), end_index.row)
+
+    return (f"{top_line}.0", f"{bot_line}.0")
+
+
+def search_for_base_character_in_pair(
+    top_index: str,
+    searchfromindex: str,
+    bot_index: str,
+    startchar: str,
+    endchar: str,
+    *,
+    backwards: bool = False,
+    charpair: str = "",
+) -> str:
+    """
+    If searching backward, count characters (e.g. parenthesis) until finding a
+    startchar which does not have a forward matching endchar.
+
+    (<= search backward will return this index
+    ()
+    START X HERE
+    ( (  )  () )
+    )<== search forward will return this index
+
+    If searching forward, count characters until finding an endchar which does
+    not have a rearward matching startchar.
+
+    Default search direction is forward.
+
+    If charpair is not specified, a default regex is constructed from startchar,
+    endchar using f"[{startchar}{endchar}]". For example,
+
+    startchar='(', endchar=')' results in: charpar='[()]'
+    """
+
+    forwards = True
+    if backwards:
+        forwards = False
+
+    if not charpair:
+        if startchar == endchar:
+            charpair = startchar
+        else:
+            charpair = f"[{startchar}{endchar}]"
+
+    if forwards:
+        plus_one_char = endchar
+        search_end_index = bot_index
+        index_offset = " +1c"
+        done_index = maintext().index("end")
+    else:
+        plus_one_char = startchar
+        search_end_index = top_index
+        index_offset = ""
+        done_index = "1.0"
+
+    at_done_index = False
+    count = 0
+
+    while True:
+        searchfromindex = maintext().search(
+            charpair,
+            searchfromindex,
+            search_end_index,
+            backwards=backwards,
+            forwards=forwards,
+            regexp=True,
+        )
+
+        if not searchfromindex:
+            break
+
+        # get one character at the identified index
+        char = maintext().get(searchfromindex)
+        if char == plus_one_char:
+            count += 1
+        else:
+            count -= 1
+
+        if count == 1:
+            break
+
+        # boundary condition exists when first char in widget is the match char
+        # need to be able to determine if search tried to go past index '1.0'
+        # if so, set index to undef and return.
+        if at_done_index:
+            searchfromindex = ""
+            break
+
+        if searchfromindex == done_index:
+            at_done_index = True
+
+        searchfromindex = maintext().index(f"{searchfromindex}{index_offset}")
+
+    return searchfromindex
+
+
+def highlight_parens_around_cursor() -> None:
+    """Highlight pair of parens that most closely brackets the cursor."""
+    highlight_single_pair_bracketing_cursor(
+        "(",
+        ")",
+        HighlightTag.PAREN,
+        HighlightColors.PAREN,
+    )
+
+
+def highlight_curly_brackets_around_cursor() -> None:
+    """Highlight pair of curly brackets that most closely brackets the cursor."""
+    highlight_single_pair_bracketing_cursor(
+        "{",
+        "}",
+        HighlightTag.CURLY_BRACKET,
+        HighlightColors.CURLY_BRACKET,
+    )
+
+
+def highlight_square_brackets_around_cursor() -> None:
+    """Highlight pair of square brackets that most closely brackets the cursor."""
+    highlight_single_pair_bracketing_cursor(
+        "[",
+        "]",
+        HighlightTag.SQUARE_BRACKET,
+        HighlightColors.SQUARE_BRACKET,
+        charpair="[][]",
+    )
+
+
+def highlight_double_quotes_around_cursor() -> None:
+    """Highlight pair of double quotes that most closely brackets the cursor."""
+    highlight_single_pair_bracketing_cursor(
+        '"',
+        '"',
+        HighlightTag.STRAIGHT_DOUBLE_QUOTE,
+        HighlightColors.STRAIGHT_DOUBLE_QUOTE,
+    )
+    highlight_single_pair_bracketing_cursor(
+        "“",
+        "”",
+        HighlightTag.CURLY_DOUBLE_QUOTE,
+        HighlightColors.CURLY_DOUBLE_QUOTE,
+    )
+
+
+def highlight_single_quotes_around_cursor() -> None:
+    """Highlight pair of single quotes that most closely brackets the cursor."""
+    highlight_single_pair_bracketing_cursor(
+        "'",
+        "'",
+        HighlightTag.STRAIGHT_SINGLE_QUOTE,
+        HighlightColors.STRAIGHT_SINGLE_QUOTE,
+    )
+    highlight_single_pair_bracketing_cursor(
+        "‘",
+        "’",
+        HighlightTag.CURLY_SINGLE_QUOTE,
+        HighlightColors.CURLY_SINGLE_QUOTE,
+    )
+
+
+def highlight_quotbrac_callback(value: bool) -> None:
+    """Callback when highlight_quotbrac preference is changed."""
+    if value:
+        highlight_quotbrac()
+    else:
+        remove_highlights_quotbrac()
+
+
+def highlight_quotbrac() -> None:
+    """Highlight all the character pairs that most closely bracket the cursor."""
+    if preferences.get(PrefKey.HIGHLIGHT_QUOTBRAC):
+        highlight_parens_around_cursor()
+        highlight_curly_brackets_around_cursor()
+        highlight_square_brackets_around_cursor()
+        highlight_double_quotes_around_cursor()
+        highlight_single_quotes_around_cursor()
+
+
+def remove_highlights_quotbrac() -> None:
+    """Remove highlights for quotes & brackets"""
+    for tag in (
+        HighlightTag.PAREN,
+        HighlightTag.CURLY_BRACKET,
+        HighlightTag.SQUARE_BRACKET,
+        HighlightTag.STRAIGHT_DOUBLE_QUOTE,
+        HighlightTag.CURLY_DOUBLE_QUOTE,
+        HighlightTag.STRAIGHT_SINGLE_QUOTE,
+        HighlightTag.CURLY_SINGLE_QUOTE,
+    ):
+        maintext().tag_delete(tag)