Implement \U, \L, \u, and \l case transformations in regex replacements.

3 files changed, 71 insertions, 5 deletions

diff --git a/docs/manual.md b/docs/manual.md
index 1efe9acc..1f1f4da4 100644
--- a/docs/manual.md
+++ b/docs/manual.md
@@ -527,9 +527,15 @@ While the pane is open in the GUI, the following key bindings apply:
 * Perform "Find Next" and "Find Prev" in the "Find" entry via `Enter` and
   `Shift+Enter`, respectively.
 * Perform "Replace" and "Replace All" in the "Replace" entry via `Enter` and
-  `Shift+Enter`, respectively. When the "Regex" find option is enabled, `\`*`n`*
-  in the "Replace" entry represents the *n*th captured matching region's text,
-  and `\0` represents all matched text.
+  `Shift+Enter`, respectively. When the "Regex" find option is enabled,
+
+  + `\`*`n`* in the "Replace" entry represents the *n*th captured matching
+    region's text, and `\0` represents all matched text.
+  + `\U` and `\L` converts everything up to the next `\L`, `\U`, or `\E` to
+    uppercase and lowercase, respectively. (`\E` turns off conversion.)
+  + `\u` and `\l` converts the next character to uppercase and lowercase,
+    respectively. These may appear within `\U` and `\L` constructs.
+
 * For at least the English locale, toggle the find options using their button
   mnemonics: `Alt+M`, `Alt+W`, `Alt+X`, `Alt+I` on Windows, Linux, and BSD, and
   `⌘M`, `⌘W`, `⌘X`, and `⌘I`, respectively, on macOS.
diff --git a/modules/textadept/find.lua b/modules/textadept/find.lua
index b8d37eed..a71faa26 100644
--- a/modules/textadept/find.lua
+++ b/modules/textadept/find.lua
@@ -381,11 +381,32 @@ local function unescape(text)
   end) or text
 end
 
+-- Replaces the text in the target range with string *text* subject to:
+-- * "\d" sequences replaced with the text of capture number *d* from the
+--   regular expression (or the entire match for *d* = 0)
+-- * "\U" and "\L" sequences convert everything up to the next "\U", "\L", or
+--   "\E" to uppercase and lowercase, respectively.
+-- * "\u" and "\l" sequences convert the next character to uppercase and
+--   lowercase, respectively. They may appear within "\U" and "\L" constructs.
+local function replace_target_re(buffer, rtext)
+  rtext = rtext:gsub('\\0', buffer.target_text):gsub('\\(%d)', buffer.tag)
+  local P, V, upper, lower = lpeg.P, lpeg.V, string.upper, string.lower
+  local patt = lpeg.Cs(P{
+    (V('text') + V('u') + V('l') + V('U') + V('L'))^1,
+    text = (1 - '\\' * lpeg.S('uUlLE'))^1,
+    u = '\\u' * lpeg.C(1) / upper, l = '\\l' * lpeg.C(1) / lower,
+    U = P('\\U') / '' * (V('text') / upper + V('u') + V('l'))^0 * V('E')^-1,
+    L = P('\\L') / '' * (V('text') / lower + V('u') + V('l'))^0 * V('E')^-1,
+    E = P('\\E') / '',
+  })
+  buffer:replace_target(lpeg.match(patt, rtext) or rtext)
+end
+
 -- Replaces found (selected) text.
 events.connect(events.REPLACE, function(rtext)
   if buffer.selection_empty then return end
   buffer:target_from_selection()
-  local f = not M.regex and buffer.replace_target or buffer.replace_target_re
+  local f = not M.regex and buffer.replace_target or replace_target_re
   f(buffer, unescape(rtext))
   buffer:set_sel(buffer.target_start, buffer.target_end)
 end)
@@ -405,7 +426,7 @@ events.connect(events.REPLACE_ALL, function(ftext, rtext)
     buffer:indicator_fill_range(e, 1)
   end
   local EOF = replace_in_sel and e == buffer.length + 1 -- no indicator at EOF
-  local f = not M.regex and buffer.replace_target or buffer.replace_target_re
+  local f = not M.regex and buffer.replace_target or replace_target_re
   rtext, repl_text = unescape(rtext), rtext -- save for ui.find.focus()
 
   -- Perform the search and replace.
diff --git a/test/test.lua b/test/test.lua
index 2d26293d..30f22433 100644
--- a/test/test.lua
+++ b/test/test.lua
@@ -2536,6 +2536,45 @@ function test_ui_find_replace_all()
   buffer:close(true)
 end
 
+function test_find_replace_regex_transforms()
+  buffer.new()
+  buffer:set_text('foObaRbaz')
+  ui.find.find_entry_text = 'f([oO]+)ba(..)'
+  ui.find.regex = true
+  local replacements = {
+    ['f\\1ba\\2'] = 'foObaRbaz',
+    ['f\\u\\1ba\\l\\2'] = 'fOObarbaz',
+    ['f\\U\\1ba\\2'] = 'fOOBARBaz',
+    ['f\\U\\1ba\\l\\2'] = 'fOOBArBaz',
+    ['f\\U\\1\\Eba\\2'] = 'fOObaRbaz',
+    ['f\\L\\1ba\\2'] = 'foobarbaz',
+    ['f\\L\\1ba\\u\\2'] = 'foobaRbaz',
+    ['f\\L\\1ba\\U\\2'] = 'foobaRBaz',
+    ['f\\L\\1\\Eba\\2'] = 'foobaRbaz',
+    ['f\\L\\u\\1ba\\2'] = 'fOobarbaz',
+    ['f\\L\\u\\1ba\\U\\l\\2'] = 'fOobarBaz',
+    ['f\\L\\u\\1\\Eba\\2'] = 'fOobaRbaz',
+    ['f\\1ba\\U\\2'] = 'foObaRBaz',
+    ['f\\1ba\\L\\2'] = 'foObarbaz',
+    ['f\\1ba\\U\\l\\2'] = 'foObarBaz',
+    [''] = 'az',
+    ['\\0'] = 'foObaRbaz'
+  }
+  for regex, replacement in pairs(replacements) do
+    ui.find.replace_entry_text = regex
+    ui.find.find_next()
+    ui.find.replace()
+    assert_equal(buffer:get_text(), replacement)
+    buffer:undo()
+    ui.find.replace_all()
+    assert_equal(buffer:get_text(), replacement)
+    buffer:undo()
+  end
+  ui.find.find_entry_text, ui.find.replace_entry_text = '', ''
+  ui.find.regex = false
+  buffer:close(true)
+end
+
 function test_history()
   local filename1 = _HOME .. '/test/modules/textadept/history/1'
   io.open_file(filename1)