[FIX] functions: name MID args

src/functions/arguments.ts

@@ -27,6 +27,9 @@ export function arg(definition: string, description: string = ""): ArgDefinition
 function makeArg(str: string): ArgDefinition {
   let parts = str.match(ARG_REGEXP)!;
   let name = parts[1].trim();
+  if (!name) {
+    throw new Error(`Function argument definition is missing a name: '${str}'.`);
+  }
   let types: ArgType[] = [];
   let isOptional = false;
   let isRepeating = false;

src/functions/module_engineering.ts

@@ -11,8 +11,8 @@ const DEFAULT_DELTA_ARG = 0;
 export const DELTA: AddFunctionDescription = {
   description: _lt("Compare two numeric values, returning 1 if they're equal."),
   args: [
-    arg(" (number)", _lt("The first number to compare.")),
-    arg(` (number, default=${DEFAULT_DELTA_ARG})`, _lt("The second number to compare.")),
+    arg("number1 (number)", _lt("The first number to compare.")),
+    arg(`number2 (number, default=${DEFAULT_DELTA_ARG})`, _lt("The second number to compare.")),
   ],
   returns: ["NUMBER"],
   compute: function (

src/functions/module_financial.ts

@@ -182,7 +182,10 @@ export const AMORLINC: AddFunctionDescription = {
       _lt("The single period within life for which to calculate depreciation.")
     ),
     arg("rate (number)", _lt("The deprecation rate.")),
-    arg(" (number, optional)", _lt("An indicator of what day count method to use.")),
+    arg(
+      "day_count_convention (number, optional)",
+      _lt("An indicator of what day count method to use.")
+    ),
   ],
   returns: ["NUMBER"],
   compute: function (

src/functions/module_text.ts

@@ -218,12 +218,12 @@ export const MID: AddFunctionDescription = {
   args: [
     arg("text (string)", _lt("The string to extract a segment from.")),
     arg(
-      " (number)",
+      "starting_at (number)",
       _lt(
         "The index from the left of string from which to begin extracting. The first character in string has the index 1."
       )
     ),
-    arg(" (number)", _lt("The length of the segment to extract.")),
+    arg("extract_length (number)", _lt("The length of the segment to extract.")),
   ],
   returns: ["STRING"],
   compute: function (