Syntax highlighting for template editor

src/calibre/gui2/dialogs/template_dialog.py

@@ -5,10 +5,193 @@ __license__   = 'GPL v3'
 
 import json
 
-from PyQt4.Qt import Qt, QDialog, QDialogButtonBox
+from PyQt4.Qt import (Qt, QDialog, QDialogButtonBox, QSyntaxHighlighter,
+                      QRegExp, QApplication,
+                      QTextCharFormat, QFont, QColor, QCursor)
+
 from calibre.gui2.dialogs.template_dialog_ui import Ui_TemplateDialog
 from calibre.utils.formatter_functions import formatter_functions
 
+class ParenPosition:
+
+    def __init__(self, block, pos, paren):
+        self.block = block
+        self.pos = pos
+        self.paren = paren
+        self.highlight = False
+
+    def set_highlight(self, to_what):
+        self.highlight = to_what
+
+class TemplateHighlighter(QSyntaxHighlighter):
+
+    Config = {}
+    Rules = []
+    Formats = {}
+    BN_FACTOR = 1000
+
+    KEYWORDS = ["program"]
+
+    def __init__(self, parent=None):
+        super(TemplateHighlighter, self).__init__(parent)
+
+        self.initializeFormats()
+
+        TemplateHighlighter.Rules.append((QRegExp(
+                "|".join([r"\b%s\b" % keyword for keyword in self.KEYWORDS])),
+                "keyword"))
+        TemplateHighlighter.Rules.append((QRegExp(
+                "|".join([r"\b%s\b" % builtin for builtin in
+                          formatter_functions.get_builtins()])),
+                "builtin"))
+
+        TemplateHighlighter.Rules.append((QRegExp(
+                r"\b[+-]?[0-9]+[lL]?\b"
+                r"|\b[+-]?0[xX][0-9A-Fa-f]+[lL]?\b"
+                r"|\b[+-]?[0-9]+(?:\.[0-9]+)?(?:[eE][+-]?[0-9]+)?\b"),
+                "number"))
+
+        stringRe = QRegExp(r"""(?:[^:]'[^']*'|"[^"]*")""")
+        stringRe.setMinimal(True)
+        TemplateHighlighter.Rules.append((stringRe, "string"))
+
+        lparenRe = QRegExp(r'\(')
+        lparenRe.setMinimal(True)
+        TemplateHighlighter.Rules.append((lparenRe, "lparen"))
+        rparenRe = QRegExp(r'\)')
+        rparenRe.setMinimal(True)
+        TemplateHighlighter.Rules.append((rparenRe, "rparen"))
+
+        self.regenerate_paren_positions()
+        self.highlighted_paren = False
+
+    def initializeFormats(self):
+        Config = self.Config
+        Config["fontfamily"] = "monospace"
+        #Config["fontsize"] = 10
+        for name, color, bold, italic in (
+                ("normal", "#000000", False, False),
+                ("keyword", "#000080", True, False),
+                ("builtin", "#0000A0", False, False),
+                ("comment", "#007F00", False, True),
+                ("string", "#808000", False, False),
+                ("number", "#924900", False, False),
+                ("lparen", "#000000", True, True),
+                ("rparen", "#000000", True, True)):
+            Config["%sfontcolor" % name] = color
+            Config["%sfontbold" % name] = bold
+            Config["%sfontitalic" % name] = italic
+
+        baseFormat = QTextCharFormat()
+        baseFormat.setFontFamily(Config["fontfamily"])
+        #baseFormat.setFontPointSize(Config["fontsize"])
+
+        for name in ("normal", "keyword", "builtin", "comment",
+                     "string", "number", "lparen", "rparen"):
+            format = QTextCharFormat(baseFormat)
+            format.setForeground(QColor(Config["%sfontcolor" % name]))
+            if Config["%sfontbold" % name]:
+                format.setFontWeight(QFont.Bold)
+            format.setFontItalic(Config["%sfontitalic" % name])
+            self.Formats[name] = format
+
+    def find_paren(self, bn, pos):
+        dex = bn * self.BN_FACTOR + pos
+        return self.paren_pos_map.get(dex, None)
+
+    def highlightBlock(self, text):
+        bn = self.currentBlock().blockNumber()
+        textLength = text.length()
+
+        self.setFormat(0, textLength, self.Formats["normal"])
+
+        if text.isEmpty():
+            pass
+        elif text[0] == "#":
+            self.setFormat(0, text.length(), self.Formats["comment"])
+            return
+
+        for regex, format in TemplateHighlighter.Rules:
+            i = regex.indexIn(text)
+            while i >= 0:
+                length = regex.matchedLength()
+                if format in ['lparen', 'rparen']:
+                    pp = self.find_paren(bn, i)
+                    if pp and pp.highlight:
+                        self.setFormat(i, length, self.Formats[format])
+                else:
+                    self.setFormat(i, length, self.Formats[format])
+                i = regex.indexIn(text, i + length)
+
+        if self.generate_paren_positions:
+            t = unicode(text)
+            i = 0
+            foundQuote = False
+            while i < len(t):
+                c = t[i]
+                if c == ':':
+                    # Deal with the funky syntax of template program mode.
+                    # This won't work if there are more than one template
+                    # expression in the document.
+                    if not foundQuote and i+1 < len(t) and t[i+1] == "'":
+                        i += 2
+                elif c in ["'", '"']:
+                    foundQuote = True
+                    i += 1
+                    j = t[i:].find(c)
+                    if j < 0:
+                        i = len(t)
+                    else:
+                        i = i + j
+                elif c in ['(', ')']:
+                    pp = ParenPosition(bn, i, c)
+                    self.paren_positions.append(pp)
+                    self.paren_pos_map[bn*self.BN_FACTOR+i] = pp
+                i += 1
+
+    def rehighlight(self):
+        QApplication.setOverrideCursor(QCursor(Qt.WaitCursor))
+        QSyntaxHighlighter.rehighlight(self)
+        QApplication.restoreOverrideCursor()
+
+    def check_cursor_pos(self, chr, block, pos_in_block):
+        found_pp = -1
+        for i, pp in enumerate(self.paren_positions):
+            pp.set_highlight(False)
+            if pp.block == block and pp.pos == pos_in_block:
+                found_pp = i
+
+        if chr not in ['(', ')']:
+            if self.highlighted_paren:
+                self.rehighlight()
+                self.highlighted_paren = False
+            return
+
+        if found_pp >= 0:
+            stack = 0
+            if chr == '(':
+                list = self.paren_positions[found_pp+1:]
+            else:
+                list = reversed(self.paren_positions[0:found_pp])
+            for pp in list:
+                if pp.paren == chr:
+                    stack += 1;
+                elif stack:
+                    stack -= 1
+                else:
+                    pp.set_highlight(True)
+                    self.paren_positions[found_pp].set_highlight(True)
+                    break
+        self.highlighted_paren = True
+        self.rehighlight()
+
+    def regenerate_paren_positions(self):
+        self.generate_paren_positions = True
+        self.paren_positions = []
+        self.paren_pos_map = {}
+        self.rehighlight()
+        self.generate_paren_positions = False
+
 class TemplateDialog(QDialog, Ui_TemplateDialog):
 
     def __init__(self, parent, text):
@@ -20,6 +203,11 @@ class TemplateDialog(QDialog, Ui_TemplateDialog):
         self.setWindowFlags(self.windowFlags()&(~Qt.WindowContextHelpButtonHint))
         self.setWindowIcon(icon)
 
+        self.last_text = ''
+        self.highlighter = TemplateHighlighter(self.textbox.document())
+        self.textbox.cursorPositionChanged.connect(self.text_cursor_changed)
+        self.textbox.textChanged.connect(self.textbox_changed)
+
         self.textbox.setTabStopWidth(10)
         self.source_code.setTabStopWidth(10)
         self.documentation.setReadOnly(True)
@@ -46,6 +234,22 @@ class TemplateDialog(QDialog, Ui_TemplateDialog):
         self.function.setCurrentIndex(0)
         self.function.currentIndexChanged[str].connect(self.function_changed)
 
+    def textbox_changed(self):
+        cur_text = unicode(self.textbox.toPlainText())
+        if self.last_text != cur_text:
+            self.last_text = cur_text
+            self.highlighter.regenerate_paren_positions()
+
+    def text_cursor_changed(self):
+        cursor = self.textbox.textCursor()
+        block_number = cursor.blockNumber()
+        pos_in_block = cursor.positionInBlock()
+        position = cursor.position()
+        t = unicode(self.textbox.toPlainText())
+        if position < len(t):
+            self.highlighter.check_cursor_pos(t[position], block_number,
+                                              pos_in_block)
+
     def function_changed(self, toWhat):
         name = unicode(toWhat)
         self.source_code.clear()