Add zettel link following style option

`g:zettel_link_following` can be set to `cursor` or `line` to change the
way zk detect the closest link to follow to (or create a new link for).

Setting it to `cursor` will look for the current word under the cursor and
decide if it is a followable link. `line` will look from the current
cursor position to the end of the line instead.

README.md

@@ -4,6 +4,11 @@ To develop / debug:
 
 start neovim with  `nvim --cmd "set rtp+=$(pwd)" .` to automatically load the files in project dir as if they were on path
 
+next up:
+* link following option (under cursor, next on line)
+* next link on line function (actions)
+* helper function to decide which one to use from A.open
+
 ## TODO: needed functionality
 
 * [ ] note creation (new anchor)
@@ -27,11 +32,13 @@ start neovim with  `nvim --cmd "set rtp+=$(pwd)" .` to automatically load the fi
  * [x] zettel extension
  * [x] link style (wiki/markdown)
   * [ ] custom link style?
+ * [ ] link detection/following (under word, next on line)
  * [ ] recursive dir lookup for zettel
  * [ ] zettel anchor regex
 
 ## TODO: nice-to-haves
 
+* [ ] refactor parsers (md/wiki) to be tables of functions/regex in options, so e.g. valid link detection can call `options.parser.isValidLink(link)` or transformation `options.parser.styleLink(anchor, text)`
 * [ ] completion engine (e.g. for `completion-nvim`, look in completion_buffers/completion-tags for reference)
 * [ ] zettel caching for big directories
 * [ ] backlinks (via rg for filename anchor?)

lua/zettelkasten/action.lua

@@ -1,11 +1,5 @@
 local A = {}
 
--- Return only the link reference portion of a markdown/wiki style link
-function A.extract_link(input)
-    if not input then return end
-    return input:match("%[%[(.+)|?.*%]%]") or input:match("%[.*%]%((.+)%)")
-end
-
 -- Extracts a file name from a link and opens the corresponding file
 -- in the current buffer.
 -- Takes an optional input parameter
@@ -23,6 +17,12 @@ function A.open_selected()
     A.open(A.get_link_under_cursor())
 end
 
+-- Return only the link reference portion of a markdown/wiki style link
+function A.extract_link(input)
+    if not input then return end
+    return input:match("%[%[(.+)|?.*%]%]") or input:match("%[.*%]%((.+)%)")
+end
+
 -- Returns the word currently under cursor, the vim equivalent of yiW.
 -- Takes an optional boolean flag to set the word being caught
 -- to the vim equivalent of doing yiw, a more exclusive version.
@@ -32,6 +32,7 @@ function A.get_link_under_cursor(small)
     local word = vim.fn.expand(c)
     return word
 end
+
 -- -- Returns the content of the line from the cursor onwards.
 -- function A.get_next_link_on_line()
 --     local line = vim.api.nvim_get_current_line()

lua/zettelkasten/options.lua

@@ -1,14 +1,16 @@
 local Opt = {}
 
 -- setting defaults
-local ZETTEL_EXTENSION = ".md"
+local ZETTEL_EXTENSION      = ".md"        -- ending of zettel files
-local ZETTEL_LINK_STYLE = "markdown"
+local ZETTEL_LINK_STYLE     = "markdown"   -- "wiki", sets the style of link to use
-local ANCHOR_SEPARATOR = "_"
+local ZETTEL_LINK_FOLLOWING = "cursor"     -- "line", sets the distance ahead to look for zettel links
+local ANCHOR_SEPARATOR      = "_"          -- separtor between anchor and link text in md links
 -- TODO zettel_root = vim.g["zettel_root"] or vim.b["zettel_root"] or "~/documents/notes",
 -- TODO zettel_anchor_pattern = regex? -> needs custom creation function in `create_anchor`
 
 -- constricted option sets
 local ZETTEL_LINK_STYLE_OPTIONS = {markdown = true, wiki = true}
+local ZETTEL_LINK_FOLLOWING_OPTIONS = { cursor = true, line = true }
 
 local function must_contain(set, value, name)
     if type(set) ~= "table" then return false end
@@ -31,6 +33,9 @@ function Opt.zettel()
     must_contain(ZETTEL_LINK_STYLE_OPTIONS, options.link_style,
                  "zettel_link_style")
 
+    options.link_following = vim.g["zettel_link_following"] or vim.b["zettel_link_following"] or ZETTEL_LINK_FOLLOWING
+    must_contain(ZETTEL_LINK_FOLLOWING_OPTIONS, options.link_following, "zettel_link_following")
+
     return options
 end
 

lua/zettelkasten/options_spec.lua

@@ -43,4 +43,19 @@ describe("zettel options", function()
         _G.vim.g.zettel_link_style = "idontbelong"
         assert.is_error(function() opt.zettel() end)
     end)
+
+    it("should return the global link following if set in vim", function()
+        _G.vim.g.zettel_link_following = "line"
+        assert.same("line", opt.zettel().link_following)
+    end)
+    it("should return the buffer link following if set in vim", function()
+        _G.vim.b.zettel_link_following = "line"
+        assert.same("line", opt.zettel().link_following)
+    end)
+    it("should return the default link following if not set in vim",
+       function() assert.same("cursor", opt.zettel().link_following) end)
+    it("should error on entries other than markdown/wiki", function()
+        _G.vim.g.zettel_link_following = "idontbelong"
+        assert.is_error(function() opt.zettel() end)
+    end)
 end)