transfer from old repo

_extensions/rchaput/acronyms/acronyms_helpers.lua

@@ -0,0 +1,65 @@
+--[[
+
+This file defines a few helper functions, in particular with respect to pandoc.
+
+--]]
+
+local Options = require("acronyms_options")
+
+
+local Helpers = {}
+
+
+-- Helper function to determine pandoc's version.
+-- `version` must be a table of numbers, e.g., `{2, 17, 0, 1}`
+function Helpers.isAtLeastVersion(version)
+    -- `PANDOC_VERSION` exists since 2.1, but we never know...
+    if PANDOC_VERSION == nil then
+        return false
+    end
+    -- Loop up over the components
+    -- e.g., `2.17.0.1` => [0]=2, [1]=17, [2]=0, [3]=1
+    for k, v in ipairs(version) do
+        if PANDOC_VERSION[k] == nil or PANDOC_VERSION[k] < version[k] then
+            -- Examples: 2.17 < 2.17.0.1, or 2.16 < 2.17
+            return false
+        elseif PANDOC_VERSION[k] > version[k] then
+            -- Example: 2.17 > 2.16.2 (we do not need to check the next!)
+            return true
+        end
+    end
+    -- At this point, all components are equal
+    return true
+end
+
+
+-- Helper function to determine whether a metadata field is a list.
+function Helpers.isMetaList(field)
+    -- We want to know whether we have multiple values (MetaList).
+    -- Pandoc 2.17 introduced a compatibility-breaking change for this:
+    --  the `.tag` is no longer present in >= 2.17 ;
+    --  the `pandoc.utils.type` function is only available in >= 2.17
+    if Helpers.isAtLeastVersion({2, 17}) then
+        -- Use the new `pandoc.utils.type` function
+        return pandoc.utils.type(field) == "List"
+    else
+        -- Use the (old) `.tag` type attribute
+        return field.t == "MetaList"
+    end
+end
+
+
+-- Helper function to generate the ID (identifier) from an acronym key.
+-- The ID can be used for, e.g., links.
+function Helpers.key_to_id(key)
+    return Options["id_prefix"] .. key
+end
+
+
+-- Similar helper but for the link itself (based on the ID).
+function Helpers.key_to_link(key)
+    return "#" .. Helpers.key_to_id(key)
+end
+
+
+return Helpers