clear tcp.mute
        clear tcp.*

        reset tcp.mute
        reset tcp.*

        set tcp.mute [0 0 10 10]
        set myvar w<100 [0 0 10 10] [20 20 10 10]
        set myvar w<100 [0 0 10 10] w<200 [20 20 10 10] [40 40 10 10]

        def square10 10 10
        set tcp.mute [0 0 square10] ; sets tcp.mute to [0 0 10 10]
        def two_coords [10 10 0 0] [0 0 10 10]
        set tcp.mute + two_coords   ; sets tcp.mute to [10 10 10 10]
        set tcp.mute w<100 two_coords ; like set.tcp.mute w<100 [10 10 0 0] [0 0 10 10]

        front tcp.solo
        front tcp.mute

   macro setall dest src
      set dest [src src src src src src src src]
      set master.##dest dest
   endmacro
   setall tcp.mute 1  ; set tcp.mute [1 1 1 1 1 1 1], set master.tcp.mute tcp.mute

Note that using ## in a macro allows the parameter to be concatenated with another named string.

        ;                variable name     description for user   default  minimum maximum
        define_parameter "hide_mute"       "Hide Mute Button"     0        0       1

        ; later in script, hide tcp.mute if hide_mute is set
        set tcp.mute hide_mute==1 [0]

        ;  note that variable name is used to make the value persist for this theme

  custom tcp.custom.xyz text_label command_id accessibility_description button_image

Layout "Mute button mixer"
  clear mcp.*
  set mcp.size [20 20]
  set mcp.mute [0 0 20 20 0 0 1 1]
EndLayout

• coordinate_list
  Coordinate lists are a sequence of values in []s. They represent a sequence of 8 values, and only one is required (any omitted values are set to 0). The meaning of these values depends on context, but for most UI elements the meaning is as follows:

          [0 0 20 20 0 0 1 1]
           ^ ^ ^  ^  ^ ^ ^ ^
           | | |  |  | | | |
           | | |  |  | | | \ bottom attach: scale the bottom edge of control with parent height by this factor
           | | |  |  | | \ right attach: scale the right edge of control with parent width by this factor
           | | |  |  | \ top attach: scale the top edge of control with parent height by this factor
           | | |  |  \ left attach: scale the left edge of control with parent width by this factor
           | | |  \ height: height of control (before edge scaling, if any)
           | | \ width: width of control (before edge scaling, if any)
           | \ top: top edge of control (before edge scaling, if any)
           \ left: left edge of control (before edge scaling, if any)
              

  Other uses:
  • *.size: the left/top coordinates are interpreted as default width/height. The width/height coordinates may specify "minimum sizes" for some contexts (notably tcp, mcp, envcp, etc). These minimum sizes aren't necessarily enforced in the UI, but instead it is kept larger with a "you're not seeing everything" image overlayed.
  • *.margin: the first four coordinates represent left, top, right, bottom margins, respectively, and the fifth coordinate represents (when supported) where to justify text (0=left,0.5=center,1=right)
  • *.color, the first four coordinates represent red, green, blue, and alpha (0-255), and the second four coordinates may specify another color (or may be ignored).
  • Additionally, some fields may use the values in other ways (as documented).
  
  
  
• scalar_value
  You can use a scalar_value as an expression in the following ways:
  1. Specifying the scalar name/value directly -- in this case, all values in the coordinate_list get this value. For example:

        set foo 1.0
          and
        set foo [1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0]
     ...or
        set foo h
          and
        set foo [h h h h h h h h]
      

     are equivalent.
  2. You can specify a scalar as a sparse coordinate_list by using the following syntax:

        scalar@x or scalar@0
        scalar@y or scalar@1
        scalar@w or scalar@2
        scalar@h or scalar@3
        scalar@ls or scalar@4
        scalar@ts or scalar@5
        scalar@rs or scalar@6
        scalar@bs or scalar@7
     

     For example, the following are equivalent:

        set foo 1.0@w
          and
        set foo [0 0 1.0 0]
     ...or
        set foo recarm@w
          and
        set foo [0 0 recarm 0]
     

  3. As a shorthand for making a sparse coordinate_list from one value of a coordinate_list, "coordlist{x}@x" can be abbreviated as "coordlist@x".
  
  
  
• operator_string expression optional_expression
  If operator_string is specified, it can contain simple expressions, and allows you to either choose or combine the following expressions. The format of operator_string is one of the following (val1/val2 can be constant or scalar_value variables, see comment below) -- note the lack of spaces in the string:

  Comparisons:
          val1<val2     --   if val1 is less than val2, use first expression, otherwise second
          val1>val2     --   if val1 is greater than val2 ...
          val1<=val2     --   if val1 is less than or equal to val2, use first expression, otherwise second
          val1>=val2     --   if val1 is greater than or equal to val2 ...
          val1==val2    --   if val1 equals val2 ...
          val1!=val2    --   if val1 does not equal val2 ...
          ?val1         --   if val1 is nonzero ...
          !val1         --   if val1 is zero ...
          val1&val2     --   bitwise AND (if any bit is set in both val1 and val2)
  
  Combinators:
          +             --   sum first expression and second expression
          -             --   subtract second expression from first expression  (REAPER 5.0+)
          *             --   multiply first expression and second expression
          /             --   divide first expression by second expression (REAPER 5.0+)
          +:val1:val2   --   val1*(first expression) + val2*(second expression)
          *:val1:val2   --   ((first expression)+[val1 val1...])*((second expression)+[val2 val2...])
   

  If optional_expression is not specified, then in its place will be the current value of the destination, which can also be abbreviated as "." -- so, for example, the following commands are all compiled to the same logic:

    set var w<100 [0]
    set var w<100 [0] .
    set var w<100 [0] var
              

• predefined scalar variables: these are variables which can be used in operator_string, or used directly as values in expressions The variables are:

          w                 -- width of parent, pixels
          h                 -- height of parent, pixels
          reaper_version    -- REAPER version (i.e. 4.25)(requires v4.15+)
          os_type           -- (REAPER 5.972+) - set to 0 on Windows, 1 on macOS, 2 on Linux
  
  Track specific:
          folderstate       -- folder state of track, if applicable (0 for normal, 1 for folder, 
                               -n for last track in folder(s))
          folderdepth       -- positive if in a folder (how many folders deep)
          maxfolderdepth    -- highest folder depth of any track
          mcp_maxfolderdepth -- highest folder depth of any track in mixer(requires v4.15+)
          recarm            -- nonzero if track record armed
          tcp_iconsize      -- size of track panel icon column, if any
          mcp_iconsize      -- size of mixer icon row, if any
          mcp_wantextmix    -- flags indicating which extended mixer settings are desired 
                               (&1 for inserts, &2 for sends, &4 for fx parms)
          tracknch          -- number of track channels (2-64)
          trackpanmode      -- pan mode of track (0=classic 3.x, 3=new balance, 5=stereo pan, 6=dualpan)
          tcp_fxparms       -- count of TCP FX parameters visible (0-n) (including sends or FX items, if visible)
          tcp_fxembed       -- (REAPER 6.0+) - count of TCP embedded FX visible
          mcp_fxembed       -- (REAPER 6.38+) count of MCP embedded FX visible
          tcp_sends_enabled -- (REAPER 7.0+) user preference to show sends in TCP is enabled
          tcp_fxlist_enabled -- (REAPER 7.0+) user preference to show FX inserts in TCP is enabled
          send_cnt          -- (REAPER 7.0+) number of sends
          fx_parm_cnt       -- (REAPER 7.0+) number of FX parameters
          fx_cnt            -- (REAPER 7.0+) number of FX inserts
          recfx_cnt         -- (REAPER 7.0+) number of record input FX
          trackcolor_valid  -- (REAPER 5.0+) - set to 1 if track color set
          trackcolor_r      -- (REAPER 5.0+) - valid if trackcolor_valid set, red value 0-255
          trackcolor_g      -- (REAPER 5.0+) - valid if trackcolor_valid set, green value 0-255
          trackcolor_b      -- (REAPER 5.0+) - valid if trackcolor_valid set, blue value 0-255
          mixer_visible     -- (REAPER 5.972+) - set to 1 if the mixer is visible
          track_selected    -- (REAPER 5.972+) - set to 1 if track is selected
          trackidx          -- (REAPER 6.47+) track index (0 for master, 1+)
          ntracks           -- (REAPER 6.47+) total track count (not including master)
          trackfixedlanes   -- (REAPER 7.0+) number of fixed lanes (or 0)
  
  Transport specific:
          trans_flags       -- trans_flags&1 is nonzero if transport centered
                               trans_flags&2 is nonzero if user wants playspeed controls visible
                               trans_flags&4 is nonzero if user wants current time signature visible
          trans_docked      -- nonzero if docked transport
          trans_center      -- nonzero if transport centered
  
  Envelope specific:
          envcp_type        -- 4 if FX envelope (can display additional controls)
          env_selected      -- (REAPER 7.0+) set to 1 if envelope is selected
  

• accessing scalar components of coordinate_list/expressions:
  A coordinate_list is composed of 8 scalar values, as described above. To convert from a named coordinate_list to a scalar value, you can use the following syntax:

     set tmp [1 2 3 4 5 6 7 8]
     tmp{x} or tmp{0}  -- first item in coordinate_list (1)
     tmp{y} or tmp{1}
     tmp{w} or tmp{2}
     tmp{h} or tmp{3}
     tmp{ls} or tmp{4}
     tmp{ts} or tmp{5}
     tmp{rs} or tmp{6}
     tmp{bs} or tmp{7}  -- last item in coordinate_list (8)
  

  So, in the above example, you can specify "tmp{y}" anywhere you would otherwise use "2". For example, instead of

    set foo w>2 [1] [0 1 2 3 4 5 6 7]
  

  you could specify

    set foo w>tmp{y} [1] [0 1 tmp{y} 3 4 5 6 7]
  

  Note: in the context of using coordinate_list names inside of [] coordinate_list, if the {} index is omitted, the current index will be used, i.e. the following are the same:

    set tmp [1 2 3 4]
    set foo [0 0 tmp tmp]
      and
    set foo [0 0 tmp{2} tmp{3}]