track enclosure state inside iffy object

1 files changed, 48 insertions, 37 deletions

diff --git a/sem-md/sem-md.lua b/sem-md/sem-md.lua
index 8b2c8b4..dc8e252 100644
--- a/sem-md/sem-md.lua
+++ b/sem-md/sem-md.lua
@@ -125,15 +125,12 @@ local SHORTNAME <const> = "sem-md"
 local PANDOC_IS_OLD <const> = PANDOC_VERSION[1] < 3
  or (PANDOC_VERSION[1] == 3 and PANDOC_VERSION[2] < 5)
 
---- pseudo-enum table to track parser enclosure state
---- @see <https://stackoverflow.com/a/70529481/18619283>
-local Enclosure = {
-  NONE = "0",
-  BRACKETED = "1",
-  BRACKETED_DONE = "2",
-  BRACED = "3",
-  BRACED_DONE = "4",
-}
+-- parser enclosure states
+local NONE <const> = 0
+local BRACKETED <const> = 1
+local BRACKETED_DONE <const> = 2
+local BRACED <const> = 3
+local BRACED_DONE <const> = 4
 
 -- element types representing content enclosure in Markdown
 local ElementTypeIsEnclosure = {
@@ -211,6 +208,10 @@ end
 local function newIffy()
   local self = {
 
+    -- flags for enclosing stages
+    -- TODO: support nested bracket enclosure
+    state = NONE,
+
     -- block has been mangled and should be returned at end of parsing
     block_is_mangled = false,
 
@@ -224,6 +225,18 @@ local function newIffy()
     chars_enclosed = ""
   }
 
+  local set_state = function(newstate)
+    assert(type(newstate) == "number"
+      and newstate >= 0
+      and newstate <= BRACED_DONE,
+      "unknown state: " .. newstate)
+    self.state = newstate
+  end
+
+  local state_is = function(expected)
+    return self.state == expected
+  end
+
   local has_bracketed_content = function()
     return not TableEmpty(self.elems_enclosed)
   end
@@ -329,6 +342,8 @@ local function newIffy()
   end
 
   return {
+    set_state = set_state,
+    state_is = state_is,
     has_bracketed_content = has_bracketed_content,
     has_no_non_brace_content = has_no_non_brace_content,
     elementize_chars_disclosed = elementize_chars_disclosed,
@@ -468,10 +483,6 @@ local function Statements (block)
     return
   end
 
-  -- flags for enclosing stages
-  -- TODO: support nested bracket enclosure
-  local encl = Enclosure.NONE
-
   -- track potentially enclosed contents
   local iffy = newIffy()
 
@@ -480,38 +491,38 @@ local function Statements (block)
 
     -- non-string element, highest state first to support fall-through
     if el.t ~= 'Str' then
-      if encl == Enclosure.BRACED_DONE then
+      if iffy.state_is(BRACED_DONE) then
 
         -- drop space after completed enclosure
         if el.t ~= "Space" then
-          encl = Enclosure.NONE
+          iffy.set_state(NONE)
         end
 
         -- fall through to parse element as unenclosed
       end
 
-      if encl == Enclosure.BRACED then
+      if iffy.state_is(BRACED) then
         iffy.append_elems_any(el)
 
         goto continue
       end
 
-      if encl == Enclosure.BRACKETED_DONE then
+      if iffy.state_is(BRACKETED_DONE) then
 
         -- bracketing not directly followed by brace
         iffy.disqualify()
-        encl = Enclosure.NONE
+        iffy.set_state(NONE)
 
         -- fall through to parse element as unenclosed
       end
 
-      if encl == Enclosure.BRACKETED then
+      if iffy.state_is(BRACKETED) then
         iffy.append_elems_any(el)
 
         goto continue
       end
 
-      if encl == Enclosure.NONE then
+      if iffy.state_is(NONE) then
 
         -- semantic annotation misparsed as Link
         -- TODO: limit to solely CURIEs in target
@@ -527,7 +538,7 @@ local function Statements (block)
 
         -- specific elements represent content enclosure
         if ElementTypeIsEnclosure[el.t] then
-          encl = Enclosure.BRACKETED_DONE
+          iffy.set_state(BRACKETED_DONE)
         end
       end
 
@@ -537,13 +548,13 @@ local function Statements (block)
     local str = el.text
 
     -- unenclosed immediately after enclosure
-    if encl == Enclosure.BRACED_DONE then
-      encl = Enclosure.NONE
+    if iffy.state_is(BRACED_DONE) then
+      iffy.set_state(NONE)
     end
 
     -- unenclosed
     -- TODO: accept backslash except immediately before bracket
-    if encl == Enclosure.NONE then
+    if iffy.state_is(NONE) then
       local _, nextpos, s = str:find("^([^%[{\\]*)")
       pos = nextpos and nextpos + 1 or pos + 1
       iffy.append_chars_unenclosed(s)
@@ -555,9 +566,9 @@ local function Statements (block)
         pos = pos + 1
         iffy.append_chars_unenclosed(t)
         if t == "[" then
-          encl = Enclosure.BRACKETED
+          iffy.set_state(BRACKETED)
         elseif t == "{" then
-          encl = Enclosure.BRACED
+          iffy.set_state(BRACED)
         end
       end
     end
@@ -565,7 +576,7 @@ local function Statements (block)
     -- in bracketed enclosure
     -- TODO: accept backslash except immediately before bracket/brace
     -- TODO: support nested bracket enclosure
-    if encl == Enclosure.BRACKETED then
+    if iffy.state_is(BRACKETED) then
       local _, nextpos, s = str:find("^([^%[%]}\\]*)", pos)
       pos = nextpos and nextpos + 1 or pos + 1
       iffy.append_chars_any(s)
@@ -574,32 +585,32 @@ local function Statements (block)
       if str:sub(pos, pos) == "]" then
         pos = pos + 1
         iffy.append_chars_unenclosed("]")
-        encl = Enclosure.BRACKETED_DONE
+        iffy.set_state(BRACKETED_DONE)
       end
     end
 
     -- exited bracketed enclosure
-    if encl == Enclosure.BRACKETED_DONE then
+    if iffy.state_is(BRACKETED_DONE) then
 
       -- entering braced enclosure
       if str:sub(pos, pos) == "{" then
         pos = pos + 1
         iffy.append_chars_unenclosed("{")
-        encl = Enclosure.BRACED
+        iffy.set_state(BRACED)
 
       -- leaving non-annotation enclosure
       else
 
         -- bracketing not directly followed by brace
         iffy.disqualify()
-        encl = Enclosure.NONE
+        iffy.set_state(NONE)
 
       end
     end
 
     -- in braced enclosure, leaving it
     -- TODO: support mixed-use enclosure
-    if encl == Enclosure.BRACED then
+    if iffy.state_is(BRACED) then
       local curie_pattern1 = "^"..CURIE_TYPE_PREFIX..CURIE_LONG.."}"
       local curie_pattern2 = "^"..CURIE_TYPE_PREFIX..CURIE_NO_REF.."}"
       local curie_pattern3 = "^"..CURIE_TYPE_PREFIX..CURIE_LOCAL.."}"
@@ -622,14 +633,14 @@ local function Statements (block)
           iffy.append_elems_enclosed(pandoc.RawInline(SHORTNAME,
             str_inside))
           iffy.qualify_enclosed()
-          encl = Enclosure.BRACED_DONE
+          iffy.set_state(BRACED_DONE)
 
         -- braced-only enclosure at beginning of block
         elseif iffy.has_no_non_brace_content() then
           iffy.append_elems_enclosed(pandoc.RawInline(SHORTNAME,
             str_inside))
           iffy.qualify_enclosed()
-          encl = Enclosure.BRACED_DONE
+          iffy.set_state(BRACED_DONE)
 
         -- braced-only enclosure at end of block
         elseif is_last_significant_element(block.content, i)
@@ -638,19 +649,19 @@ local function Statements (block)
           iffy.append_elems_enclosed(pandoc.RawInline(SHORTNAME,
             str_inside))
           iffy.qualify_enclosed()
-          encl = Enclosure.BRACED_DONE
+          iffy.set_state(BRACED_DONE)
 
         -- stray braced-only enclosure
         else
           iffy.append_chars_unenclosed(str_inside .. "}")
           iffy.disqualify()
-          encl = Enclosure.NONE
+          iffy.set_state(NONE)
         end
 
         -- TODO: parse str_remains for another enclosure
         if str_remains:len() > 0 then
           iffy.append_elems_unenclosed(str_remains)
-          encl = Enclosure.NONE
+          iffy.set_state(NONE)
         end
       end
     end