Improve argument count linting

Closes #15

CHANGELOG.md

@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+0.10
+---
+
+* Exclude optional arguments when linting argument count
+* Lint minimum argument count
+
 0.9
 ---
 

src/linter.ts

@@ -38,14 +38,18 @@ export const expressionLanguageLinterSource = (state: EditorState) => {
         if (!args) {
           return;
         }
+        const argCountMin = args.reduce((count, arg) => count + Number(!arg.optional), 0);
+        const argCountMax = args.length;
+        const argumentCountHintFn = () => `<code>${fn.name}</code> takes ${argCountMin == argCountMax ? `exactly ${argCountMax}` : `${argCountMin}–${argCountMax}`} argument${argCountMax == 1 ? '' : 's'}`;
+        let i = 0;
 
-        for (let n = node.node.firstChild, i = 0; n != null; n = n.nextSibling) {
+        for (let n = node.node.firstChild; n != null; n = n.nextSibling) {
           if (n.type.is(BlockComment)) {
             continue;
           }
 
-          if (i > args.length - 1) {
-            diagnostics.push({ from: n.from, to: n.to, severity: 'warning', message: `Unexpected argument – <code>${fn.name}</code> takes ${args.length} argument${args.length == 1 ? '' : 's'}` });
+          if (i > argCountMax - 1) {
+            diagnostics.push({ from: n.from, to: n.to, severity: 'warning', message: `Unexpected argument – ${argumentCountHintFn()}` });
             continue;
           }
 
@@ -58,6 +62,10 @@ export const expressionLanguageLinterSource = (state: EditorState) => {
           i++;
         }
 
+        if (i < argCountMin) {
+          diagnostics.push({ from: node.from, to: node.to, severity: 'error', message: `Too few arguments – ${argumentCountHintFn()}` });
+        }
+
         break;
       case Property:
       case Method:

test/test-linter.ts

@@ -23,7 +23,7 @@ const config = {
   ],
   functions: [
     {name: "smh", args: [], returnType: ["string"]},
-    {name: "any_fn", args: [{name: "anything", type: ["any"]}], returnType: ["any"]},
+    {name: "any_fn", args: [{name: "anything", type: ["any"]}, {name: "optional", optional: true}], returnType: ["any"]},
     {name: "smash_my_head", args: [{name: "object", type: ["object"]}]},
     {name: "getObject", returnType: ["custom44"]},
   ],
@@ -92,7 +92,32 @@ describe("Expression language linting", () => {
     ist(diagnostics.length, 1);
     ist(diagnostics[0].from, 18);
     ist(diagnostics[0].to, 19);
-    ist(diagnostics[0].message, "Unexpected argument – <code>smash_my_head</code> takes 1 argument");
+    ist(diagnostics[0].message, "Unexpected argument – <code>smash_my_head</code> takes exactly 1 argument");
+  });
+
+  it("complains about too many arguments when there are optional arguments", () => {
+    const diagnostics = get("any_fn(1, 2, 3)");
+
+    ist(diagnostics.length, 1);
+    ist(diagnostics[0].from, 13);
+    ist(diagnostics[0].to, 14);
+    ist(diagnostics[0].message, "Unexpected argument – <code>any_fn</code> takes 1–2 arguments");
+  });
+
+  it("complains about too few arguments", () => {
+    const diagnostics = get("smash_my_head()");
+    ist(diagnostics.length, 1);
+    ist(diagnostics[0].from, 13);
+    ist(diagnostics[0].to, 15);
+    ist(diagnostics[0].message, "Too few arguments – <code>smash_my_head</code> takes exactly 1 argument");
+  });
+
+  it("complains about too few arguments when there are optional arguments", () => {
+    const diagnostics = get("any_fn()");
+    ist(diagnostics.length, 1);
+    ist(diagnostics[0].from, 6);
+    ist(diagnostics[0].to, 8);
+    ist(diagnostics[0].message, "Too few arguments – <code>any_fn</code> takes 1–2 arguments");
   });
 
   it("complains about wrong argument type using constant", () => {