--- a/runtime/pack/dist/opt/termdebug/plugin/termdebug.vim
+++ b/runtime/pack/dist/opt/termdebug/plugin/termdebug.vim
@@ -148,9 +148,9 @@ enddef
 def Highlight(init: bool, old: string, new: string)
   var default = init ? 'default ' : ''
   if new ==# 'light' && old !=# 'light'
-    exe "hi " .. default .. "debugPC term=reverse ctermbg=lightblue guibg=lightblue"
+    exe $"hi {default}debugPC term=reverse ctermbg=lightblue guibg=lightblue"
   elseif new ==# 'dark' && old !=# 'dark'
-    exe "hi " .. default .. "debugPC term=reverse ctermbg=darkblue guibg=darkblue"
+    exe $"hi {default}debugPC term=reverse ctermbg=darkblue guibg=darkblue"
   endif
 enddef
 
@@ -183,17 +183,17 @@ def GetCommand(): list<string>
 enddef
 
 def Echoerr(msg: string)
-  echohl ErrorMsg | echom '[termdebug] ' .. msg | echohl None
+  echohl ErrorMsg | echom $'[termdebug] {msg}' | echohl None
 enddef
 
 def StartDebug(bang: bool, ...gdb_args: list<string>)
   # First argument is the command to debug, second core file or process ID.
-  StartDebug_internal({'gdb_args': gdb_args, 'bang': bang})
+  StartDebug_internal({gdb_args: gdb_args, bang: bang})
 enddef
 
 def StartDebugCommand(bang: bool, ...args: list<string>)
   # First argument is the command to debug, rest are run arguments.
-  StartDebug_internal({'gdb_args': [args[0]], 'proc_args': args[1 : ], 'bang': bang})
+  StartDebug_internal({gdb_args: [args[0]], proc_args: args[1 : ], bang: bang})
 enddef
 
 
@@ -204,7 +204,7 @@ def StartDebug_internal(dict: dict<any>)
   endif
   var gdbcmd = GetCommand()
   if !executable(gdbcmd[0])
-    Echoerr('Cannot execute debugger program "' .. gdbcmd[0] .. '"')
+    Echoerr($'Cannot execute debugger program "{gdbcmd[0]}"')
     return
   endif
 
@@ -272,13 +272,13 @@ enddef
 
 # Use when debugger didn't start or ended.
 def CloseBuffers()
-  exe 'bwipe! ' .. ptybuf
-  exe 'bwipe! ' .. commbuf
+  exe $'bwipe! {ptybuf}'
+  exe $'bwipe! {commbuf}'
   if asmbuf > 0 && bufexists(asmbuf)
-    exe 'bwipe! ' .. asmbuf
+    exe $'bwipe! {asmbuf}'
   endif
   if varbuf > 0 && bufexists(varbuf)
-    exe 'bwipe! ' .. varbuf
+    exe $'bwipe! {varbuf}'
   endif
   running = 0
   gdbwin = 0
@@ -292,7 +292,8 @@ def CheckGdbRunning(): string
     gdbproc_status = job_status(gdbproc)
   endif
   if gdbproc == v:null || gdbproc_status !=# 'run'
-    Echoerr(string(GetCommand()[0]) .. ' exited unexpectedly')
+    var cmd_name = string(GetCommand()[0])
+    Echoerr($'{cmd_name} exited unexpectedly')
     CloseBuffers()
     return ''
   endif
@@ -313,7 +314,7 @@ def StartDebug_term(dict: dict<any>)
   if vvertical
     # Assuming the source code window will get a signcolumn, use two more
     # columns for that, thus one less for the terminal window.
-    exe ":" .. (&columns / 2 - 1) .. "wincmd |"
+    exe $":{(&columns / 2 - 1)}wincmd |"
     if allleft
       # use the whole left column
       wincmd H
@@ -328,7 +329,7 @@ def StartDebug_term(dict: dict<any>)
   })
   if commbuf == 0
     Echoerr('Failed to open the communication terminal window')
-    exe 'bwipe! ' .. ptybuf
+    exe $'bwipe! {ptybuf}'
     return
   endif
   var commpty = job_info(term_getjob(commbuf))['tty_out']
@@ -363,7 +364,7 @@ def StartDebug_term(dict: dict<any>)
   # Adding arguments requested by the user
   gdb_cmd += gdb_args
 
-  ch_log('executing "' .. join(gdb_cmd) .. '"')
+  ch_log($'executing "{join(gdb_cmd)}"')
   gdbbuf = term_start(gdb_cmd, {
     term_name: 'gdb',
     term_finish: 'close',
@@ -405,12 +406,12 @@ def StartDebug_term(dict: dict<any>)
   # ---- gdb started. Next, let's set the MI interface. ---
   # Set arguments to be run.
   if len(proc_args)
-    term_sendkeys(gdbbuf, 'server set args ' .. join(proc_args) .. "\r")
+    term_sendkeys(gdbbuf, $"server set args {join(proc_args)}\r")
   endif
 
   # Connect gdb to the communication pty, using the GDB/MI interface.
   # Prefix "server" to avoid adding this to the history.
-  term_sendkeys(gdbbuf, 'server new-ui mi ' .. commpty .. "\r")
+  term_sendkeys(gdbbuf, $"server new-ui mi {commpty}\r")
 
   # Wait for the response to show up, users may not notice the error and wonder
   # why the debugger doesn't work.
@@ -456,7 +457,7 @@ def StartDebug_term(dict: dict<any>)
     return
   endif
 
-  job_setoptions(term_getjob(gdbbuf), {'exit_cb': function('EndTermDebug')})
+  job_setoptions(term_getjob(gdbbuf), {exit_cb: function('EndTermDebug')})
 
   # Set the filetype, this can be used to add mappings.
   set filetype=termdebug
@@ -493,7 +494,7 @@ def StartDebug_prompt(dict: dict<any>)
   if vvertical
     # Assuming the source code window will get a signcolumn, use two more
     # columns for that, thus one less for the terminal window.
-    exe ":" .. (&columns / 2 - 1) .. "wincmd |"
+    exe $":{(&columns / 2 - 1)}wincmd |"
   endif
 
   var gdb_args = get(dict, 'gdb_args', [])
@@ -514,14 +515,14 @@ def StartDebug_prompt(dict: dict<any>)
   # Adding arguments requested by the user
   gdb_cmd += gdb_args
 
-  ch_log('executing "' .. join(gdb_cmd) .. '"')
+  ch_log($'executing "{join(gdb_cmd)}"')
   gdbjob = job_start(gdb_cmd, {
     exit_cb: function('EndPromptDebug'),
     out_cb: function('GdbOutCallback'),
   })
   if job_status(gdbjob) != "run"
     Echoerr('Failed to start gdb')
-    exe 'bwipe! ' .. promptbuf
+    exe $'bwipe! {promptbuf}'
     return
   endif
   exe $'au BufUnload <buffer={promptbuf}> ++once ' ..
@@ -547,16 +548,16 @@ def StartDebug_prompt(dict: dict<any>)
     endif
     ptywin = win_getid()
     var pty = job_info(term_getjob(ptybuf))['tty_out']
-    SendCommand('tty ' .. pty)
+    SendCommand($'tty {pty}')
 
     # Since GDB runs in a prompt window, the environment has not been set to
     # match a terminal window, need to do that now.
     SendCommand('set env TERM = xterm-color')
-    SendCommand('set env ROWS = ' .. winheight(ptywin))
-    SendCommand('set env LINES = ' .. winheight(ptywin))
-    SendCommand('set env COLUMNS = ' .. winwidth(ptywin))
-    SendCommand('set env COLORS = ' .. &t_Co)
-    SendCommand('set env VIM_TERMINAL = ' .. v:version)
+    SendCommand($'set env ROWS = {winheight(ptywin)}')
+    SendCommand($'set env LINES = {winheight(ptywin)}')
+    SendCommand($'set env COLUMNS = {winwidth(ptywin)}')
+    SendCommand($'set env COLORS = {&t_Co}')
+    SendCommand($'set env VIM_TERMINAL = {v:version}')
   else
     # TODO: open a new terminal, get the tty name, pass on to gdb
     SendCommand('show inferior-tty')
@@ -566,7 +567,7 @@ def StartDebug_prompt(dict: dict<any>)
 
   # Set arguments to be run
   if len(proc_args)
-    SendCommand('set args ' .. join(proc_args))
+    SendCommand($'set args {join(proc_args)}')
   endif
 
   StartDebugCommon(dict)
@@ -576,7 +577,7 @@ enddef
 def StartDebugCommon(dict: dict<any>)
   # Sign used to highlight the line where the program has stopped.
   # There can be only one.
-  sign_define('debugPC', {'linehl': 'debugPC'})
+  sign_define('debugPC', {linehl: 'debugPC'})
 
   # Install debugger commands in the text window.
   win_gotoid(sourcewin)
@@ -610,11 +611,11 @@ enddef
 
 # Send a command to gdb.  "cmd" is the string without line terminator.
 def SendCommand(cmd: string)
-  ch_log('sending to gdb: ' .. cmd)
+  ch_log($'sending to gdb: {cmd}')
   if way == 'prompt'
-    ch_sendraw(gdb_channel, cmd .. "\n")
+    ch_sendraw(gdb_channel, $"{cmd}\n")
   else
-    term_sendkeys(commbuf, cmd .. "\r")
+    term_sendkeys(commbuf, $"{cmd}\r")
   endif
 enddef
 
@@ -642,7 +643,7 @@ enddef
 # This is global so that a user can create their mappings with this.
 def TermDebugSendCommand(cmd: string)
   if way == 'prompt'
-    ch_sendraw(gdb_channel, cmd .. "\n")
+    ch_sendraw(gdb_channel, $"{cmd}\n")
   else
     var do_continue = 0
     if !stopped
@@ -651,7 +652,7 @@ def TermDebugSendCommand(cmd: string)
       sleep 10m
     endif
     # TODO: should we prepend CTRL-U to clear the command?
-    term_sendkeys(gdbbuf, cmd .. "\r")
+    term_sendkeys(gdbbuf, $"{cmd}\r")
     if do_continue
       ContinueCommand()
     endif
@@ -668,7 +669,7 @@ def SendResumingCommand(cmd: string)
     ch_log('assume that program is running after this command')
     SendCommand(cmd)
   else
-    ch_log('dropping command, program is running: ' .. cmd)
+    ch_log($'dropping command, program is running: {cmd}')
   endif
 enddef
 
@@ -696,7 +697,7 @@ enddef
 
 # Function called when gdb outputs text.
 def GdbOutCallback(channel: channel, text: string)
-  ch_log('received from gdb: ' .. text)
+  ch_log($'received from gdb: {text}')
 
   # Disassembly messages need to be forwarded as-is.
   if parsing_disasm_msg > 0
@@ -746,7 +747,7 @@ enddef
 # - change \\ to \
 def DecodeMessage(quotedText: string, literal: bool): string
   if quotedText[0] != '"'
-    Echoerr('DecodeMessage(): missing quote in ' .. quotedText)
+    Echoerr($'DecodeMessage(): missing quote in {quotedText}')
     return ''
   endif
   var msg = quotedText
@@ -805,7 +806,7 @@ def EndTermDebug(job: any, status: any)
   endif
 
   if bufexists(commbuf)
-    exe 'bwipe! ' .. commbuf
+    exe $'bwipe! {commbuf}'
   endif
   gdbwin = 0
   EndDebugCommon()
@@ -815,13 +816,13 @@ def EndDebugCommon()
   var curwinid = win_getid()
 
   if bufexists(ptybuf)
-    exe 'bwipe! ' .. ptybuf
+    exe $'bwipe! {ptybuf}'
   endif
   if bufexists(asmbuf)
-    exe 'bwipe! ' .. asmbuf
+    exe $'bwipe! {asmbuf}'
   endif
   if bufexists(varbuf)
-    exe 'bwipe! ' .. varbuf
+    exe $'bwipe! {varbuf}'
   endif
   running = 0
 
@@ -830,7 +831,7 @@ def EndDebugCommon()
   var was_buf = bufnr()
   for bufnr in signcolumn_buflist
     if bufexists(bufnr)
-      exe ":" .. bufnr .. "buf"
+      exe $":{bufnr}buf"
       if exists('b:save_signcolumn')
         &signcolumn = b:save_signcolumn
         unlet b:save_signcolumn
@@ -838,7 +839,7 @@ def EndDebugCommon()
     endif
   endfor
   if bufexists(was_buf)
-    exe ":" .. was_buf .. "buf"
+    exe $":{was_buf}buf"
   endif
 
   DeleteCommands()
@@ -872,7 +873,7 @@ def EndPromptDebug(job: any, status: any
   endif
 
   if bufexists(promptbuf)
-    exe 'bwipe! ' .. promptbuf
+    exe $'bwipe! {promptbuf}'
   endif
 
   EndDebugCommon()
@@ -904,10 +905,10 @@ def HandleDisasmMsg(msg: string)
       set nomodified
       set filetype=asm
 
-      var lnum = search('^' .. asm_addr)
+      var lnum = search($'^{asm_addr}')
       if lnum != 0
-        sign_unplace('TermDebug', {'id': asm_id})
-        sign_place(asm_id, 'TermDebug', 'debugPC', '%', {'lnum': lnum})
+        sign_unplace('TermDebug', {id: asm_id})
+        sign_place(asm_id, 'TermDebug', 'debugPC', '%', {lnum: lnum})
       endif
 
       win_gotoid(curwinid)
@@ -966,8 +967,8 @@ def HandleVariablesMsg(msg: string)
   if win_gotoid(varwin)
     silent! :%delete _
     var spaceBuffer = 20
-    setline(1, 'Type' ..
-          repeat(' ', 16) ..  'Name' ..  repeat(' ', 16) ..  'Value')
+    var spaces = repeat(' ', 16)
+    setline(1, $'Type{spaces}Name{spaces}Value')
     var cnt = 1
     var capture = '{name=".\{-}",\%(arg=".\{-}",\)\{0,1\}type=".\{-}"\%(,value=".\{-}"\)\{0,1\}}'
     var varinfo = matchstr(msg, capture, 0, cnt)
@@ -1251,9 +1252,8 @@ def Until(at: string)
     ch_log('assume that program is running after this command')
 
     # Use the fname:lnum format
-    var AT = empty(at) ?
-          fnameescape(expand('%:p')) .. ':' .. line('.') : at
-    SendCommand('-exec-until ' .. AT)
+    var AT = empty(at) ? $"{fnameescape(expand('%:p'))}:{line('.')}" : at
+    SendCommand($'-exec-until {AT}')
   else
     ch_log('dropping command, program is running: exec-until')
   endif
@@ -1271,16 +1271,15 @@ def SetBreakpoint(at: string, tbreak=fal
   endif
 
   # Use the fname:lnum format, older gdb can't handle --source.
-  var AT = empty(at) ?
-    fnameescape(expand('%:p')) .. ':' .. line('.') : at
+  var AT = empty(at) ? $"{fnameescape(expand('%:p'))}:{line('.')}" : at
   var cmd = ''
   if tbreak
-    cmd = '-break-insert -t ' .. AT
+    cmd = $'-break-insert -t {AT}'
   else
-    cmd = '-break-insert ' .. AT
+    cmd = $'-break-insert {AT}'
   endif
   # OK
-  # echom "cmsd: " .. cmd
+  # echom $"cmsd: {cmd}"
   SendCommand(cmd)
   if do_continue
     ContinueCommand()
@@ -1297,7 +1296,7 @@ def ClearBreakpoint()
     for id in breakpoint_locations[bploc]
       if has_key(breakpoints, id)
         # Assume this always works, the reply is simply "^done".
-        SendCommand('-break-delete ' .. id)
+        SendCommand($'-break-delete {id}')
         for subid in keys(breakpoints[id])
           sign_unplace('TermDebug',
             {id: Breakpoint2SignNumber(id, str2nr(subid))})
@@ -1315,18 +1314,18 @@ def ClearBreakpoint()
       if empty(breakpoint_locations[bploc])
         remove(breakpoint_locations, bploc)
       endif
-      echomsg 'Breakpoint ' .. nr .. ' cleared from line ' .. lnum .. '.'
+      echomsg $'Breakpoint {nr} cleared from line {lnum}.'
     else
-      Echoerr('Internal error trying to remove breakpoint at line ' .. lnum .. '!')
+      Echoerr($'Internal error trying to remove breakpoint at line {lnum}!')
     endif
   else
-    echomsg 'No breakpoint to remove at line ' .. lnum .. '.'
+    echomsg $'No breakpoint to remove at line {lnum}.'
   endif
 enddef
 
 def Run(args: string)
   if args != ''
-    SendResumingCommand('-exec-arguments ' .. args)
+    SendResumingCommand($'-exec-arguments {args}')
   endif
   SendResumingCommand('-exec-run')
 enddef
@@ -1340,13 +1339,13 @@ def Frame(arg: string)
   # already parsed and allows for more formats
   if arg =~ '^\d\+$' || arg == ''
     # specify frame by number
-    SendCommand('-interpreter-exec mi "frame ' .. arg .. '"')
+    SendCommand($'-interpreter-exec mi "frame {arg}"')
   elseif arg =~ '^0x[0-9a-fA-F]\+$'
     # specify frame by stack address
-    SendCommand('-interpreter-exec mi "frame address ' .. arg .. '"')
+    SendCommand($'-interpreter-exec mi "frame address {arg}"')
   else
     # specify frame by function name
-    SendCommand('-interpreter-exec mi "frame function ' .. arg .. '"')
+    SendCommand($'-interpreter-exec mi "frame function {arg}"')
   endif
 enddef
 
@@ -1373,14 +1372,14 @@ def SendEval(expr: string)
   var expr_escaped = expr
     ->substitute('\\', '\\\\', 'g')
     ->substitute('"', '\\"', 'g')
-  SendCommand('-data-evaluate-expression "' .. expr_escaped .. '"')
+  SendCommand($'-data-evaluate-expression "{expr_escaped}"')
   evalexpr = exprLHS
 enddef
 
 # :Evaluate - evaluate what is specified / under the cursor
 def Evaluate(range: number, arg: string)
   var expr = GetEvaluationExpression(range, arg)
-  #echom "expr:" .. expr
+  #echom $"expr: {expr}"
   ignoreEvalError = 0
   SendEval(expr)
 enddef
@@ -1451,19 +1450,19 @@ def HandleEvaluate(msg: string)
         \ ->substitute(NullRepl, '\\000', 'g')
   if evalFromBalloonExpr
     if evalFromBalloonExprResult == ''
-      evalFromBalloonExprResult = evalexpr .. ': ' .. value
+      evalFromBalloonExprResult = $'{evalexpr}: {value}'
     else
-      evalFromBalloonExprResult ..= ' = ' .. value
+      evalFromBalloonExprResult ..= $' = {value}'
     endif
     balloon_show(evalFromBalloonExprResult)
   else
-    echomsg '"' .. evalexpr .. '": ' .. value
+    echomsg $'"{evalexpr}": {value}'
   endif
 
   if evalexpr[0] != '*' && value =~ '^0x' && value != '0x0' && value !~ '"$'
     # Looks like a pointer, also display what it points to.
     ignoreEvalError = 1
-    SendEval('*' .. evalexpr)
+    SendEval($'*{evalexpr}')
   else
     evalFromBalloonExpr = 0
   endif
@@ -1537,7 +1536,7 @@ def GotoAsmwinOrCreateIt()
       # 60 is approx spaceBuffer * 3
       if winwidth(0) > (78 + 60)
         mdf = 'vert'
-        exe mdf .. ' ' .. ':60' .. 'new'
+        exe $'{mdf} :60new'
       else
         exe 'rightbelow new'
       endif
@@ -1556,7 +1555,7 @@ def GotoAsmwinOrCreateIt()
     setlocal modifiable
 
     if asmbuf > 0 && bufexists(asmbuf)
-      exe 'buffer' .. asmbuf
+      exe $'buffer {asmbuf}'
     elseif empty(glob('Termdebug-asm-listing'))
       silent file Termdebug-asm-listing
       asmbuf = bufnr('Termdebug-asm-listing')
@@ -1567,19 +1566,19 @@ def GotoAsmwinOrCreateIt()
     endif
 
     if mdf != 'vert' && GetDisasmWindowHeight() > 0
-      exe 'resize ' .. GetDisasmWindowHeight()
+      exe $'resize {GetDisasmWindowHeight()}'
     endif
   endif
 
   if asm_addr != ''
-    var lnum = search('^' .. asm_addr)
+    var lnum = search($'^{asm_addr}')
     if lnum == 0
       if stopped
         SendCommand('disassemble $pc')
       endif
     else
-      sign_unplace('TermDebug', {'id': asm_id})
-      sign_place(asm_id, 'TermDebug', 'debugPC', '%', {'lnum': lnum})
+      sign_unplace('TermDebug', {id: asm_id})
+      sign_place(asm_id, 'TermDebug', 'debugPC', '%', {lnum: lnum})
     endif
   endif
 enddef
@@ -1612,7 +1611,7 @@ def GotoVariableswinOrCreateIt()
       # 60 is approx spaceBuffer * 3
       if winwidth(0) > (78 + 60)
         mdf = 'vert'
-        exe mdf .. ' ' .. ':60' .. 'new'
+        exe $'{mdf} :60new'
       else
         exe 'rightbelow new'
       endif
@@ -1630,7 +1629,7 @@ def GotoVariableswinOrCreateIt()
     setlocal modifiable
 
     if varbuf > 0 && bufexists(varbuf)
-      exe 'buffer' .. varbuf
+      exe $'buffer {varbuf}'
     elseif empty(glob('Termdebug-variables-listing'))
       silent file Termdebug-variables-listing
       varbuf = bufnr('Termdebug-variables-listing')
@@ -1641,7 +1640,7 @@ def GotoVariableswinOrCreateIt()
     endif
 
     if mdf != 'vert' && GetVariablesWindowHeight() > 0
-      exe 'resize ' .. GetVariablesWindowHeight()
+      exe $'resize {GetVariablesWindowHeight()}'
     endif
   endif
 
@@ -1680,12 +1679,12 @@ def HandleCursor(msg: string)
       var curwinid = win_getid()
       var lnum = 0
       if win_gotoid(asmwin)
-        lnum = search('^' .. asm_addr)
+        lnum = search($'^{asm_addr}')
         if lnum == 0
           SendCommand('disassemble $pc')
         else
-          sign_unplace('TermDebug', {'id': asm_id})
-          sign_place(asm_id, 'TermDebug', 'debugPC', '%', {'lnum': lnum})
+          sign_unplace('TermDebug', {id: asm_id})
+          sign_place(asm_id, 'TermDebug', 'debugPC', '%', {lnum: lnum})
         endif
 
         win_gotoid(curwinid)
@@ -1702,7 +1701,7 @@ def HandleCursor(msg: string)
     if lnum =~ '^[0-9]*$'
       GotoSourcewinOrCreateIt()
       if expand('%:p') != fnamemodify(fname, ':p')
-        echomsg 'different fname: "' .. expand('%:p') .. '" vs "' .. fnamemodify(fname, ':p') .. '"'
+        echomsg $"different fname: '{expand('%:p')}' vs '{fnamemodify(fname, ':p')}'"
         augroup Termdebug
           # Always open a file read-only instead of showing the ATTENTION
           # prompt, since it is unlikely we want to edit the file.
@@ -1714,19 +1713,19 @@ def HandleCursor(msg: string)
         augroup END
         if &modified
           # TODO: find existing window
-          exe 'split ' .. fnameescape(fname)
+          exe $'split {fnameescape(fname)}'
           sourcewin = win_getid()
           call InstallWinbar(0)
         else
-          exe 'edit ' .. fnameescape(fname)
+          exe $'edit {fnameescape(fname)}'
         endif
         augroup Termdebug
           au! SwapExists
         augroup END
       endif
-      exe ":" .. lnum
+      exe $":{lnum}"
       normal! zv
-      sign_unplace('TermDebug', {'id': pc_id})
+      sign_unplace('TermDebug', {id: pc_id})
       sign_place(pc_id, 'TermDebug', 'debugPC', fname,
             {lnum: str2nr(lnum), priority: 110})
       if !exists('b:save_signcolumn')
@@ -1736,7 +1735,7 @@ def HandleCursor(msg: string)
       setlocal signcolumn=yes
     endif
   elseif !stopped || fname != ''
-    sign_unplace('TermDebug', {'id': pc_id})
+    sign_unplace('TermDebug', {id: pc_id})
   endif
 
   win_gotoid(wid)
@@ -1762,7 +1761,7 @@ def CreateBreakpoint(id: number, subid: 
         label = 'F+'
       endif
     endif
-    sign_define('debugBreakpoint' .. nr,
+    sign_define($'debugBreakpoint{nr}',
       {text: slice(label, 0, 2),
         texthl: hiName})
   endif
@@ -1783,7 +1782,7 @@ def HandleNewBreakpoint(msg: string, mod
     if msg =~ 'pending='
       nr = substitute(msg, '.*number=\"\([0-9.]*\)\".*', '\1', '')
       var target = substitute(msg, '.*pending=\"\([^"]*\)\".*', '\1', '')
-      echomsg 'Breakpoint ' .. nr .. ' (' .. target  .. ') pending.'
+      echomsg $'Breakpoint {nr} ({target}) pending.'
     endif
     return
   endif
@@ -1831,9 +1830,9 @@ def HandleNewBreakpoint(msg: string, mod
     var posMsg = ''
     if bufloaded(fname)
       PlaceSign(id, subid, entry)
-      posMsg = ' at line ' .. lnum .. '.'
+      posMsg = $' at line {lnum}.'
     else
-      posMsg = ' in ' .. fname .. ' at line ' .. lnum .. '.'
+      posMsg = $' in {fname} at line {lnum}.'
     endif
     var actionTaken = ''
     if !modifiedFlag
@@ -1843,7 +1842,7 @@ def HandleNewBreakpoint(msg: string, mod
     else
       actionTaken = 'enabled'
     endif
-    echom 'Breakpoint ' .. nr .. ' ' .. actionTaken .. posMsg
+    echom $'Breakpoint {nr} {actionTaken}{posMsg}'
   endfor
 enddef
 
@@ -1851,7 +1850,7 @@ enddef
 def PlaceSign(id: number, subid: number, entry: dict<any>)
   var nr = printf('%d.%d', id, subid)
   sign_place(Breakpoint2SignNumber(id, subid), 'TermDebug',
-    'debugBreakpoint' .. nr, entry['fname'],
+    $'debugBreakpoint{nr}', entry['fname'],
     {lnum: entry['lnum'], priority: 110})
   entry['placed'] = 1
 enddef
@@ -1867,12 +1866,12 @@ def HandleBreakpointDelete(msg: string)
     for [subid, entry] in items(breakpoints[id])
       if has_key(entry, 'placed')
         sign_unplace('TermDebug',
-          {'id': Breakpoint2SignNumber(str2nr(id), str2nr(subid))})
+          {id: Breakpoint2SignNumber(str2nr(id), str2nr(subid))})
         remove(entry, 'placed')
       endif
     endfor
     remove(breakpoints, id)
-    echomsg 'Breakpoint ' .. id .. ' cleared.'
+    echomsg $'Breakpoint {id} cleared.'
   endif
 enddef
 
@@ -1884,7 +1883,7 @@ def HandleProgramRun(msg: string)
     return
   endif
   pid = nr
-  ch_log('Detected process ID: ' .. pid)
+  ch_log($'Detected process ID: {pid}')
 enddef
 
 # Handle a BufRead autocommand event: place any signs.