Initial commit.

syntax.lua

@@ -0,0 +1,122 @@
+local keywords = {
+    "and", "break", "do", "else", "elseif", "end", --[["false",]] "for", "function",
+    "goto", "if", "in", --[["local", "nil",]] "not", "or", "repeat", "return",
+    "then", --[["true",]] "until", "while"
+}
+local keyword_set = {}
+for _, kw in ipairs(keywords) do
+    keyword_set[kw] = true
+end
+
+local keyword_value_set = {
+    ["true"] = true,
+    ["false"] = true,
+    ["nil"] = true,
+    ["local"] = true,
+    ["math.huge"] = true
+}
+
+local function colorize(str, color)
+    return "<style color="..(theme.styles["syntax_"..color] or "#fff")..">"..str.."</style>"
+end
+
+function syntax_highlight(code)
+    local out = ""
+    local pos = 1
+    while pos <= #code do
+        local matched = false
+
+        -- Whitespace
+        local ws_start, ws_end = code:find("^%s+", pos)
+        if ws_start then
+            out = out..colorize(code:sub(ws_start, ws_end), "whitespace")
+            pos = ws_end + 1
+            matched = true
+        end
+
+        -- Single-line comment
+        if not matched then
+            local com_start, com_end = code:find("^%-%-[^\n]*", pos)
+            if com_start then
+                out = out..colorize(code:sub(com_start, com_end), "comment")
+                pos = com_end + 1
+                matched = true
+            end
+        end
+
+        -- String (double-quoted, simple escape handling)
+        if not matched then
+            local str_start, str_end = code:find('^"[^"]*"', pos)
+            if str_start then
+                out = out..colorize(code:sub(str_start, str_end), "string")
+                pos = str_end + 1
+                matched = true
+            end
+        end
+
+        -- String (single-quoted, similar)
+        if not matched then
+            local str_start, str_end = code:find("^'[^']*", pos)
+            if str_start then
+                out = out..colorize(code:sub(str_start, str_end), "string")
+                pos = str_end + 1
+                matched = true
+            end
+        end
+
+        -- Documentation placeholders. These aren't in Lua, but that means they
+        -- can be highlighted without worrying about confusing alternative meanings.
+        if not matched then
+            local str_start, str_end = code:find('^\\?<[^>]*>', pos)
+            if str_start then
+                out = out..colorize(code:sub(str_start, str_end), "placeholder")
+                pos = str_end + 1
+                matched = true
+            end
+        end
+
+        -- Number (basic integer/float)
+        if not matched then
+            local num_start, num_end = code:find("^%d+%.?%d*[eE]?[+-]?%d*", pos)
+            if num_start then
+                out = out..colorize(code:sub(num_start, num_end), "number")
+                pos = num_end + 1
+                matched = true
+            end
+        end
+
+        -- Identifier/Keyword
+        if not matched then
+            local id_start, id_end, id_text = code:find("^([%a_][%w_]*)", pos)
+            if id_start then
+                if keyword_set[id_text] then
+                    out = out..colorize(id_text, "keyword")
+                elseif keyword_value_set[id_text] then
+                    out = out..colorize(id_text, "keyword_value")
+                else
+                    out = out..colorize(id_text, "identifier")
+                end
+                pos = id_end + 1
+                matched = true
+            end
+        end
+
+        -- Operators/Punctuation (catch-all for non-alphanumeric)
+        if not matched then
+            local op_start, op_end = code:find("^[^%s%a%d_\"'{}(),%][]", pos)
+            if op_start then
+                local op = code:sub(op_start, op_end)
+                out = out..colorize(op, op == "-" and code:sub(op_end +1, op_end +2):find "^%d" and "number" or "operator")
+                pos = op_end + 1
+                matched = true
+            end
+        end
+
+        -- If nothing matched, advance to avoid infinite loop (e.g., invalid char)
+        if not matched then
+            out = out..colorize(code:sub(pos, pos), "generic")
+            pos = pos + 1
+        end
+    end
+    return out
+end