feat: current indent

Co-authored-by: Lukas Reineke <lukas.reineke@protonmail.com>
Co-authored-by: Daniel Kongsgaard <daniel@Daniels-MBP.home>

doc/indent_blankline.txt

@@ -201,6 +201,9 @@ config                                                            *ibl.config*
    • {scope}            (|ibl.config.scope|)
                         Configures the scope
 
+   • {current_indent}   (|ibl.config.current_indent|)
+                        Configures the current_indent
+
    • {exclude}          (|ibl.config.exclude|)
                         Configures what is excluded from indent-blankline
 
@@ -366,9 +369,11 @@ config.scope                                                *ibl.config.scope*
 
  Configures the scope
 
- The scope is *not* the current indentation level! Instead, it is the
- indentation level where variables or functions are accessible. This depends
- on the language you are writing.
+ The scope is *not* the current indentation level!
+ See |ibl.config.current_indent| if you want to highlight the current
+ indentation.
+ Instead, scope it is the indentation level where variables or functions
+ are accessible. This depends on the language you are writing.
 
  Example: ~
 
@@ -541,6 +546,78 @@ config.scope.exclude                                *ibl.config.scope.exclude*
    }
 <
 
+config.current_indent                                *ibl.config.current_indent*
+
+ Configures the current indent
+
+ The current indent *is* just the current indentation level (unlike scope).
+
+ Example: ~
+
+ In Python, using the same example as for scope, current indent will
+ highlight the current inner most indentation guide. With scope disabled,
+ this will look like this:
+ >python
+ def foo();
+     if True:
+     ┋   a = "foo █ar"
+     ┋   #        ↳ cursor here
+     print(a)
+<
+ If we have the same code with scope enabled, it will look like this:
+ >python
+ def foo();
+ ┋   if True:
+ ┋   ┋   a = "foo █ar"
+ ┋   ┋   #        ↳ cursor here
+ ┋   print(a)
+<
+ If you have both scope and current indent enabled, and the two overlap,
+ |ibl.config.scope.priority| and |ibl.config.current_indent.priority| will
+ determine which is displayed.
+
+ Fields: ~
+                                           *ibl.config.current_indent.enabled*
+   • {enabled}     (boolean)
+                   Enables or disables current indent
+
+                   Default: `false` ~
+
+                                              *ibl.config.current_indent.char*
+   • {char}        (string)
+                   Character that gets used to display the current
+                   indentation guide
+                   Each character has to have a display width
+                   of 0 or 1
+
+                   Default: |ibl.config.indent.char| ~
+
+                                         *ibl.config.current_indent.highlight*
+   • {highlight}   (string)
+                   Highlight group that gets applied to the current
+                   indent
+
+                   Default: |hl-IblCurrentIndent| ~
+
+                                        *ibl.config.current_indent.show_start*
+   • {show_start}  (boolean)
+                   Shows an underline on the line above the current indent
+
+                   Default: `true` ~
+
+                                          *ibl.config.current_indent.show_end*
+   • {show_end}    (boolean)
+                   Shows an underline on the line of the current indent
+
+                   Default: `true` ~
+
+                                          *ibl.config.current_indent.priority*
+   • {priority}    (number)
+                   Virtual text priority for the current indent
+
+                   Default: `1023` ~
+
+
 config.exclude                                            *ibl.config.exclude*
 
  Configures what is excluded from indent-blankline
@@ -591,7 +668,6 @@ indent.whitespace                                      *ibl.indent.whitespace*
    • {SPACE}
    • {INDENT}
 
-
 hooks                                                              *ibl.hooks*
 
  Hooks provide a way to extend the functionality of indent-blankline. Either
@@ -611,10 +687,12 @@ hooks.type                                                    *ibl.hooks.type*
  Variants: ~
    • {ACTIVE}
    • {SCOPE_ACTIVE}
+   • {CURRENT_INDENT_ACTIVE}
    • {SKIP_LINE}
    • {WHITESPACE}
    • {VIRTUAL_TEXT}
    • {SCOPE_HIGHLIGHT}
+   • {CURRENT_INDENT_HIGHLIGHT}
    • {CLEAR}
    • {HIGHLIGHT_SETUP}
 
@@ -653,6 +731,20 @@ hooks.cb.scope_active({bufnr})                    *ibl.hooks.cb.scope_active()*
    (boolean)
 
 
+hooks.cb.current_indent_active({bufnr}) *ibl.hooks.cb.current_indent_active()*
+
+ Callback function for the |ibl.hooks.type|.CURRENT_INDENT_ACTIVE hook.
+
+ Gets called before refreshing indent-blankline for a buffer.
+ If the callback returns false, |ibl.config.current_indent| will be disabled.
+
+ Parameters: ~
+   • {bufnr}  (number) Buffer number
+
+ Return: ~
+   (boolean)
+
+
 hooks.cb.skip_line({tick}, {bufnr}, {row}, {line})  *ibl.hooks.cb.skip_line()*
 
  Callback function for the |ibl.hooks.type|.SKIP_LINE hook.
@@ -727,6 +819,26 @@ hooks.cb.scope_highlight({tick}, {bufnr}, {scope}, {scope_index})
    (number)
 
 
+                                     *ibl.hooks.cb.current_indent_highlight()*
+hooks.cb.current_indent_highlight({tick}, {bufnr}, {current_indent}, {current_indent_index})
+
+ Callback function for the |ibl.hooks.type|.CURRENT_INDENT_HIGHLIGHT hook.
+
+ Gets called for once per refresh after the current indent is determined.
+ The return value overwrites the index of the highlight group
+ defined in |ibl.config.current_indent.highlight|
+
+ Parameters: ~
+   • {tick}                  (number) auto-incrementing id of the
+                                      current refresh
+   • {bufnr}                 (number) Buffer number
+   • {current_indent}        (ibl.current_indent) The current scope
+   • {current_indent_index}  (number) Index of the highlight group
+
+ Return: ~
+   (number)
+
+
 hooks.cb.clear({bufnr})                                 *ibl.hooks.cb.clear()*
 
  Callback function for the |ibl.hooks.type|.CLEAR hook.
@@ -800,6 +912,35 @@ hooks.builtin.scope_highlight_from_extmark
      hooks.type.SCOPE_HIGHLIGHT,
      hooks.builtin.scope_highlight_from_extmark
    )
+<
+                         *hooks.builtin.current_indent_highlight_from_extmark*
+hooks.builtin.current_indent_highlight_from_extmark
+
+ Gets the highlight group from existing extmark highlights at the end or
+ beginning of the current indent.
+ This can be used to get a somewhat reliable sync between
+ "rainbow parentheses" plugins like
+ https://gitlab.com/HiPhish/rainbow-delimiters.nvim and indent-blankline.
+
+ Example: ~
+   >lua
+   local highlight = {
+     "RainbowDelimiterRed",
+     "RainbowDelimiterYellow",
+     "RainbowDelimiterBlue",
+     "RainbowDelimiterOrange",
+     "RainbowDelimiterGreen",
+     "RainbowDelimiterViolet",
+     "RainbowDelimiterCyan",
+   }
+   vim.g.rainbow_delimiters = { highlight = highlight }
+   require "ibl".setup { scope = { highlight = highlight } }
+
+   local hooks = require "ibl.hooks"
+   hooks.register(
+     hooks.type.CURRENT_INDENT_HIGHLIGHT,
+     hooks.builtin.current_indent_highlight_from_extmark
+   )
 <
                              *ibl.hooks.builtin.hide_first_space_indent_level*
 hooks.builtin.hide_first_space_indent_level
@@ -852,6 +993,12 @@ IblScope                                                         *hl-IblScope*
 
  Default: takes the values from |hl-LineNr| when not defined ~
 
+IblCurrentIndent                                         *hl-IblCurrentIndent*
+
+ The default highlight group for |ibl.config.current_indent| characters.
+
+ Default: takes the values from |hl-LineNr| when not defined ~
+
 ==============================================================================
  5. COMMANDS                                                    *ibl.commands*
 

lua/ibl/config.lua

@@ -62,6 +62,17 @@ M.default_config = {
             },
         },
     },
+    current_indent = {
+        enabled = false,
+        char = nil,
+        show_start = true,
+        show_end = true,
+        highlight = "IblCurrentIndent",
+        priority = 1023,
+        exclude = {
+            filetypes = {},
+        },
+    },
     exclude = {
         filetypes = {
             "lspinfo",
@@ -116,6 +127,7 @@ local validate_config = function(config)
         indent = { config.indent, "table", true },
         whitespace = { config.whitespace, "table", true },
         scope = { config.scope, "table", true },
+        current_indent = { config.current_indent, "table", true },
         exclude = { config.exclude, "table", true },
     }, config, "ibl.config")
 
@@ -229,6 +241,43 @@ local validate_config = function(config)
         end
     end
 
+    if config.current_indent then
+        utils.validate({
+            enabled = { config.current_indent.enabled, "boolean", true },
+            char = { config.current_indent.char, { "string", "table" }, true },
+            show_start = { config.current_indent.show_start, "boolean", true },
+            show_end = { config.current_indent.show_end, "boolean", true },
+            highlight = { config.current_indent.highlight, { "string", "table" }, true },
+            priority = { config.current_indent.priority, "number", true },
+            exclude = { config.current_indent.exclude, "table", true },
+        }, config.current_indent, "ibl.config.current_indent")
+        if config.current_indent.char then
+            vim.validate {
+                char = {
+                    config.current_indent.char,
+                    validate_char,
+                    "current_indent.char to have a display width of 0 or 1",
+                },
+            }
+        end
+        if type(config.current_indent.highlight) == "table" then
+            vim.validate {
+                tab_char = {
+                    config.current_indent.highlight,
+                    function(highlight)
+                        return #highlight > 0
+                    end,
+                    "current_indent.highlight to be not empty",
+                },
+            }
+        end
+        if config.current_indent.exclude then
+            utils.validate({
+                filetypes = { config.current_indent.exclude.filetypes, "table", true },
+            }, config.current_indent.exclude, "ibl.config.current_indent.exclude")
+        end
+    end
+
     if config.exclude then
         if config.exclude then
             utils.validate({

lua/ibl/config.types.lua

@@ -15,6 +15,8 @@
 ---@field whitespace ibl.config.whitespace?
 --- Configures the scope
 ---@field scope ibl.config.scope?
+--- Configures the current_indent
+---@field current_indent ibl.config.current_indent?
 --- Configures what is excluded from indent-blankline
 ---@field exclude ibl.config.exclude?
 
@@ -109,6 +111,28 @@
 --- </code>
 ---@field node_type table<string, string[]>?
 
+---@class ibl.config.current_indent
+--- Enables or disables current indent
+---@field enabled boolean?
+--- Character, or list of characters, that get used to display the current indent indentation guide
+---
+--- Each character has to have a display width of 0 or 1
+---@field char string|string[]?
+--- Shows an underline on the first line of the current indent
+---@field show_start boolean?
+--- Shows an underline on the last line of the current indent
+---@field show_end boolean?
+--- Highlight group, or list of highlight groups, that get applied to the current indent
+---@field highlight string|string[]?
+--- Virtual text priority for the current indent
+---@field priority number?
+--- Configures filetypes to be excluded from current indent
+---@field exclude ibl.config.current_indent.exclude?
+
+---@class ibl.config.current_indent.exclude
+--- List of filetypes for which current indent is disabled
+---@field filetypes string[]?
+
 ---@class ibl.config.exclude
 --- List of `filetypes` for which indent-blankline is disabled
 ---@field filetypes string[]?
@@ -131,6 +155,8 @@
 ---@field whitespace ibl.config.full.whitespace: ibl.config.whitespace
 --- Configures the scope
 ---@field scope ibl.config.full.scope: ig.config.scope
+--- Configures the current_indent
+---@field current_indent ibl.config.full.current_indent
 --- Configures what is excluded from indent-blankline
 ---@field exclude ibl.config.full.exclude: ibl.config.exclude
 
@@ -225,6 +251,28 @@
 --- </code>
 ---@field node_type table<string, string[]>
 
+---@class ibl.config.full.current_indent
+--- Enables or disables current indent
+---@field enabled boolean
+--- Character, or list of characters, that get used to display the current indent indentation guide
+---
+--- Each character has to have a display width of 0 or 1
+---@field char string|string[]?
+--- Shows an underline on the first line of the current indent
+---@field show_start boolean
+--- Shows an underline on the last line of the current indent
+---@field show_end boolean
+--- Highlight group, or list of highlight groups, that get applied to the current indent
+---@field highlight string|string[]
+--- Virtual text priority for the current indent
+---@field priority number
+--- Configures filetypes to be excluded from current indent
+---@field exclude ibl.config.full.current_indent.exclude
+
+---@class ibl.config.full.current_indent.exclude
+--- List of filetypes for which current indent is disabled
+---@field filetypes string[]
+
 ---@class ibl.config.full.exclude: ibl.config.exclude
 --- List of `filetypes` for which indent-blankline is disabled
 ---@field filetypes string[]