feat: 2.08 IF and ELSE IF support

TODO.md

@@ -0,0 +1,34 @@
+Error if `DIM z(size)` isn't called before usage
+
+```
+100 PROC x(a(),size,2) TO result:PRINT result:STOP
+110 DEFPROC x(inp(),size,y)
+120 LOCAL z(),tot
+130 DIM z(size)
+140 tot=0
+150 FOR i=1 TO size:z(i)=inp(i)*y:NEXT i
+160 FOR i=1 TO size:tot=tot+z(i):NEXT i
+170 ENDPROC = tot
+```
+
+
+
+---
+
+
+Test defaults in defproc:
+
+```
+100 PROC x(12,,"bob"):STOP
+110 DEFPROC x(a=1,b$="alice",c$,d=-5)
+120 LOCAL e=3
+130 PRINT a,b$,c$,d,e
+140 ENDPROC
+```
+
+---
+
+## Validation
+
+- Validate missing `ENDIF`
+- `IF 0` alone should fail … right?

__tests__/index.test.js

@@ -96,3 +96,26 @@ test('validateTxt', (t) => {
   const res = validateTxt(src);
   t.is(res.length, 0, 'no errors');
 });
+
+test('exact matches', (t) => {
+  const tests = [
+    `10 %a=1
+20 PRINT (%a)+1`,
+    `100 REPEAT
+110 INPUT n
+120 IF n=33 THEN EXIT 150
+130 REPEAT UNTIL n < 0
+140 PRINT "Loop completed normally": STOP
+150 PRINT "Loop ended early": STOP`,
+  ];
+
+  tests.forEach((src) => {
+    src = src
+      .split('\n')
+      .map((_) => _.trim())
+      .join('\n');
+    const bytes = file2bas(src);
+    const txt = file2txt(bytes);
+    t.is(txt.trim(), src.trim(), 'matches');
+  });
+});

__tests__/txt2bas.test.js

@@ -103,17 +103,7 @@ test('comments', (t) => {
 test('end with $', (t) => {
   let src = '202 IF INKEY$="s"';
   let expect = [
-    0x00,
-    0xca,
-    0x07,
-    0x00,
-    0xfa,
-    0xa6,
-    0x3d,
-    0x22,
-    0x73,
-    0x22,
-    0x0d,
+    0x00, 0xca, 0x07, 0x00, 0xfa, 0xa6, 0x3d, 0x22, 0x73, 0x22, 0x0d,
   ];
 
   const res = Array.from(parseLine(src));
@@ -303,6 +293,16 @@ test('INT function', (t) => {
   t.is(token.name, 'NUMBER');
 });
 
+test('ELSE IF', (t) => {
+  let src, res;
+  src = '20 ELSE IF 1 < 2 PRINT "ELSE"';
+  res = parseLines(src).statements[0];
+
+  t.is(res.tokens[0].text, 'ELSE', 'has else');
+  t.is(res.tokens[1].text, 'IF', 'then if');
+  t.is(res.tokens[1].value, 0x83, 'correct IF value for following ELSE');
+});
+
 test('in the wild', (t) => {
   let src, res;
 

__tests__/validate.test.js

@@ -17,17 +17,17 @@ function contains(str) {
   };
 }
 
-test('test bad if', (t) => {
-  const src = '10 IF 0';
-  const line = asBasic(src);
-  t.throws(
-    () => {
-      validateStatement(line);
-    },
-    contains('IF statement must have THEN'),
-    src
-  );
-});
+// test('test bad if', (t) => {
+//   const src = '10 IF 0';
+//   const line = asBasic(src);
+//   t.throws(
+//     () => {
+//       validateStatement(line);
+//     },
+//     contains('IF statement must have THEN'),
+//     src
+//   );
+// });
 
 test('validator works with autoline', async (t) => {
   const fixture = await readFile(__dirname + '/fixtures/autoline.txt');
@@ -184,9 +184,22 @@ notThrows(
 );
 notThrows('10   %a = 10');
 notThrows('10 PRINT ("TRUE" AND b)+("FALSE" AND NOT b)');
+notThrows('100 PROC x(12,,”bob”):STOP');
+notThrows('120 PRINT name$');
+notThrows('10 DEF FN ian$(REF jenny$(),index)=jenny$(index)');
+notThrows('10 LET x,y = y,x');
+notThrows('10 a,b,c,d$,e$,f = 1,2,3,"xyz","zzz",g*h');
+notThrows('10 y$ *= 2');
+notThrows('120 PRINT "Press a key for left":x=INPUT -2');
+notThrows('10 " Hello There! "[<+->]');
+notThrows('10 a$(5)[-](3 TO 7)[<]');
+notThrows('30 PRINT "perftest() took ";TIME;" frames"');
+notThrows('20 PRINT %a+1');
+notThrows('20 %a=1');
 
 /********************************************/
 
+// throws('20 PRINT (%a)+1');
 throws(
   '330 REPEAT UNTIL %(c=13) AND %(j > 8)',
   'Cannot redeclare integer expression'
@@ -202,7 +215,7 @@ throws('10 DEFPROC _foo()', 'Function names can only contain letters');
 throws('10 DEFPROC 5foo()', 'Function names can only contain letters');
 
 throws('760 ', 'Empty line');
-throws('945 IF %i = 20 ENDPROC', 'IF statement must have THEN');
+// throws('945 IF %i = 20 ENDPROC', 'IF statement must have THEN');
 throws('10 % sprite continue %', 'Cannot redeclare integer expression whilst');
 throws('10 IF %b=%c THEN ENDPROC', 'Cannot redeclare integer expression', {
   message: 'integer expression function on either side of IF comparator',

codes.js

@@ -9,8 +9,8 @@ export default {
   // new in 2.08
   0x81: 'TIME',
   0x82: 'PRIVATE',
-  0x83: 'ELSEIF',
-  0x84: 'ENDIF', // internal use only: displays as IF, but indicates ELSE is present on same line
+  0x83: 'IF', // internal use only: displays as IF (which is managed here), but is converted from 0x83 via the aliases in op-table
+  0x84: 'ENDIF',
   0x85: 'EXIT',
   0x86: 'REF',
 

txt2bas/index.js

@@ -68,6 +68,14 @@ import {
  * @property {Statement} value
  */
 
+/**
+ * Where a bank starts
+ *
+ * @typedef BankSplit
+ * @property {string} bankFile the filename
+ * @property {number} line the starting line
+ */
+
 /**
  * Auto increment line
  *
@@ -202,6 +210,7 @@ export function parseLineWithData(line, autoline = null) {
  * @property {string} filename
  * @property {Autoline} autoline
  * @property {Define[]} defines
+ * @property {BankSplit[]} bankSplits
  */
 
 /**
@@ -229,6 +238,8 @@ export function parseLines(
   let filename = null;
   const defines = [];
 
+  const bankSplits = [];
+
   const autoline = new Autoline();
 
   for (let i = 0; i < lines.length; i++) {
@@ -242,6 +253,11 @@ export function parseLines(
           filename = line.split(' ')[1];
         }
 
+        if (line.startsWith('#bankfile ')) {
+          const bankFile = line.split(' ')[1];
+          bankSplits.push({ bank: bankFile, line: i + 1 });
+        }
+
         if (line.startsWith('#autoline')) {
           autoline.parse(line);
         }
@@ -311,6 +327,7 @@ export function parseLines(
     filename,
     autoline,
     defines,
+    bankSplits,
   };
 }
 
@@ -758,6 +775,23 @@ export class Statement {
     return this.line.substring(start, pos);
   }
 
+  peekPrevToken(at = this.pos) {
+    let pos = at - 1;
+    const end = pos;
+    let allowSpace = true;
+    while (pos >= 0 || tests._isDigit(this.line.charAt(pos))) {
+      if (tests._isSpace(this.line.charAt(pos)) && !allowSpace) {
+        pos++;
+        break;
+      }
+      if (tests._isSpace(this.line.charAt(pos))) {
+        allowSpace = false;
+      }
+      pos--;
+    }
+    return this.line.substring(pos, end);
+  }
+
   findOpCode(endPos) {
     const peek = this.peek(endPos);
     const moreToken = tests._isAlpha(peek);
@@ -771,8 +805,16 @@ export class Statement {
       return false;
     }
 
+    if (curr === 'IF') {
+      // look for ELSE before hand
+      const prev = this.peekPrevToken();
+      if (prev === 'ELSE') {
+        curr = 'ELSE IF';
+      }
+    }
+
     // be wary that this could be something like `DEF FN`
-    if (peek === ' ' && !opTable[curr]) {
+    else if (peek === ' ' && !opTable[curr]) {
       const next = this.peekToken(endPos + 1).toUpperCase();
       const test = `${curr} ${next}`;
 

txt2bas/op-table.js

@@ -11,5 +11,6 @@ export const opTable = Object.entries(codes).reduce(
     GOSUB: 0xed,
     RAND: 0xf9,
     CONT: 0xe8,
+    'ELSE IF': 0x83,
   }
 );

txt2bas/validator.js

@@ -144,10 +144,11 @@ class Scope {
   }
 
   /**
-   * @returns {Token}
+   * @returns {Token|null}
    */
   peekNext() {
     let next = this.tokens[0];
+    if (!next) return null;
     if (next.name === WHITE_SPACE) next = this.tokens[1];
     return next;
   }
@@ -343,6 +344,8 @@ export function validateStatement(tokens, debug = {}) {
         // scope state
         scope.push(OUTER_IF);
         scope.push(IF);
+
+        // should I look ahead for a THEN to detect the type of IF?
       }
 
       if (value === opTable.UNTIL) {
@@ -358,8 +361,14 @@ export function validateStatement(tokens, debug = {}) {
         scope.resetExpression();
       }
 
-      if (value === opTable.ELSE && scope.includes(OUTER_IF)) {
-        throw new Error('Statement separator (:) expected before ELSE');
+      if (value === opTable.ELSE) {
+        const next = scope.peekNext();
+
+        if (next && next.text === IF) {
+          // change the token to ELSEIF and drop the IF
+        } else if (scope.includes(OUTER_IF)) {
+          throw new Error('Statement separator (:) expected before ELSE');
+        }
       }
 
       if (
@@ -675,7 +684,11 @@ export function validateStatementStarters(token, scope) {
  */
 export function validateEndOfStatement(scope) {
   if (scope.includes(IF)) {
-    throw new Error('IF statement must have THEN');
+    if (parser.getParser() === parser.v207) {
+      throw new Error('IF statement must have THEN');
+    } else {
+      // we need to stack up an open IF statement
+    }
   }
 
   const open = scope.findIndex((_) => _.startsWith('OPEN_'));