gaps: allow optional px suffix

docs/userguide

@@ -1455,15 +1455,15 @@ to most specific as some directives can overwrite others.
 *Syntax*:
 -----------------------
 # Inner gaps for all windows: space between two adjacent windows (or split containers).
-gaps inner <gap_size_in_px>
+gaps inner <gap_size>[px]
 
 # Outer gaps for all windows: space along the screen edges.
-gaps outer|horizontal|vertical|top|left|bottom|right <gap_size_in_px>
+gaps outer|horizontal|vertical|top|left|bottom|right <gap_size>[px]
 
 # Inner and outer gaps for all windows on a specific workspace.
 # <ws> can be a workspace number or name.
-workspace <ws> gaps inner <gap_size_in_px>
-workspace <ws> gaps outer|horizontal|vertical|top|left|bottom|right <gap_size_in_px>
+workspace <ws> gaps inner <gap_size>[px]
+workspace <ws> gaps outer|horizontal|vertical|top|left|bottom|right <gap_size>[px]
 
 # Enabling “Smart Gaps” means no gaps will be shown when there is
 # precisely one window or split container on the workspace.

parser-specs/commands.spec

@@ -111,6 +111,12 @@ state GAPS_WITH_SCOPE:
 
 state GAPS_WITH_MODE:
   value = word
+      -> GAPS_END
+
+state GAPS_END:
+  'px'
+      ->
+  end
       -> call cmd_gaps($type, $scope, $mode, $value)
 
 state BORDER_WIDTH:

parser-specs/config.spec

@@ -68,13 +68,19 @@ state IGNORE_LINE:
   line
       -> INITIAL
 
-# gaps inner|outer|horizontal|vertical|top|right|bottom|left <px>
+# gaps inner|outer|horizontal|vertical|top|right|bottom|left <gap_size>[px]
 state GAPS:
   scope = 'inner', 'outer', 'horizontal', 'vertical', 'top', 'right', 'bottom', 'left'
       -> GAPS_WITH_SCOPE
 
 state GAPS_WITH_SCOPE:
   value = number
+      -> GAPS_END
+
+state GAPS_END:
+  'px'
+      ->
+  end
       -> call cfg_gaps($workspace, $scope, &value)
 
 # smart_borders true|false

testcases/t/319-gaps.t

@@ -22,7 +22,7 @@ use i3test i3_config => <<EOT;
 font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
 
 gaps inner 10
-gaps outer 20
+gaps outer 20px
 
 default_border pixel 0
 EOT