moved the list numbering to helpers

1 files changed, 111 insertions, 0 deletions

diff --git a/rst_helpers.lua b/rst_helpers.lua
index a635996..b30370a 100644
--- a/rst_helpers.lua
+++ b/rst_helpers.lua
@@ -590,5 +590,116 @@ function helpers.table.simple(raw)
     return rows
 end
 
+helpers.list = {}
+
+do
+    local c = {}
+    c.roman = S"ivxlcdm"^1
+    c.Roman = S"IVXLCDM"^1
+    c.alpha = R"az" - P"i"
+    c.Alpha = R"AZ" - P"I"
+    c.digit = R"09"^1
+    c.auto  = P"#"
+
+    local stripme   = S" ()."
+    local dontstrip = 1 - stripme
+    local itemstripper = stripme^0 * C(dontstrip^1) * stripme^0
+
+    local con = function (str)
+        --print("This is it: >"..str.."<")
+        str = itemstripper:match(str)
+        for conv, pat in next, c do
+            if pat:match(str) then
+                return conv
+            end
+        end
+        return false
+    end
+    helpers.list.conversion = con
+
+    local rnums = {
+        i = 1,
+        v = 5,
+        x = 10,
+        l = 50,
+        c = 100,
+        d = 500,
+        m = 1000,
+    }
+
+    local function roman_to_arab (str)
+        local n = 1
+        local curr, succ
+        local max_three = { }
+        local value = 0
+        while n <= #str do
+            if curr and curr == max_three[#max_three] then
+                if #max_three >= 3 then
+                    return "Not a number"
+                else
+                    max_three[#max_three+1] = curr
+                end     
+            else    
+                max_three = { curr }
+            end     
+
+            curr = rnums[str:sub(n,n)]
+
+            n = n + 1
+            succ = str:sub(n,n)
+
+            if succ and succ ~= "" then
+                succ = rnums[succ]
+                if curr < succ then
+                    --n = n + 1
+                    --value = value + succ - curr
+                    value = value  - curr
+                else    
+                    value = value + curr
+                end     
+            else    
+                value = value + curr
+            end     
+        end     
+        return value
+    end
+    helpers.list.roman_to_arab = roman_to_arab
+
+    local suc = function (str, old)
+        str, old = itemstripper:match(str), itemstripper:match(old)
+        local n_str, n_old = tonumber(str), tonumber(old)
+        if n_str and n_old then -- arabic numeral
+            return n_str == n_old + 1
+        end
+
+        local con_str, con_old = con(str), con(old)
+        if con_str == "alpha"  or
+           con_str == "Alpha" then
+            return str:byte() == old:byte() + 1
+        else -- “I'm a Roman!” - “A woman?” - “No, *Roman*! - Au!” - “So your father was a woman?”
+            if not (str:lower() == str  or
+                    str:upper() == str) then -- uneven cased --> fail
+                return false
+            end
+
+
+            local trc = state.roman_cache
+            n_str = trc[str] or nil
+            n_old = trc[old] or nil
+            if not n_str then
+                n_str = roman_to_arab(str:lower())
+                trc[str] = n_str
+            end
+            if not n_old then
+                n_old = roman_to_arab(old:lower())
+                trc[old] = n_old
+            end
+            --print(n_str, n_old, n_str == n_old + 1 )
+            return n_str == n_old + 1 
+        end
+    end
+    helpers.list.successor = suc
+end
+
 return helpers