From f55aa51023c2e094ddfc9a41c00dbb46f2d33b7d Mon Sep 17 00:00:00 2001
From: Joshua Bell <inexorabletash@gmail.com>
Date: Sun, 28 Dec 2014 20:55:23 -0700
Subject: [PATCH] Make line numbers relevant; resolves issue #5

---
 README.md                    |  1 -
 basic.js                     | 38 +++++++++++++++++++++++++++++-------
 samples/sample.unittests.txt | 20 +++++++++++++------
 3 files changed, 45 insertions(+), 14 deletions(-)

diff --git a/README.md b/README.md
index f4338cd..65e9032 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,6 @@ Notes & Known Issues
 * The BASIC program is compiled to JavaScript before execution. Syntax errors are therefore detected at compile-time rather than at run-time as on a traditional interpreter. For example, the following program would run without errors on an Apple since the erroneous second statement is never reached. `10 END : CHR$(PRINT)`
 * Handling of BASIC code that does not match the canonical `LIST` output format may not behave as on an Apple:
   * Keyword parsing differs from Applesoft command line. For example `FOR I = S TO P` doesn't collapse into `FOR I = STOP`.
-  * The interpreter doesn't actually care about line numbers for statement ordering (just for `GOTO/GOSUB` targets and `IF` statements). So `20 PRINT "A"`, `10 PRINT "B"` will just print `A`, then `B`
 * Limitations:
   * Floating point overflow is only detected on variable assignment.
   * Only a subset of DOS 3.3 and ProDOS useful for basic file I/O are implemented.
diff --git a/basic.js b/basic.js
index 1c530e8..141b149 100644
--- a/basic.js
+++ b/basic.js
@@ -2132,24 +2132,48 @@ this.basic = (function() {
         function parseStatement() {
           if (test('data')) {
             program.data = program.data.concat(match('data'));
-            return;
+            return undefined;
           } else if (test('remark', void 0, true)) {
-            return;
+            return undefined;
           } else if (test('reserved') || test('identifier')) {
-            program.statements.push(mkfun(parseCommand()));
+            return mkfun(parseCommand());
           } else {
             // So TRACE output is correct
-            program.statements.push(empty_statement);
+            return empty_statement;
           }
         }
 
         // Line = line-number Statement { separator Statement }
         function parseLine() {
-          program.statements.push(match('lineNumber'));
-          parseStatement();
+          var num = match('lineNumber');
+          var statements = [];
+          var statement = parseStatement();
+          if (statement) statements.push(statement);
           while (test('separator', ':', true)) {
-            parseStatement();
+            statement = parseStatement();
+            if (statement) statements.push(statement);
           }
+          insertLine(num, statements);
+        }
+
+        function insertLine(number, statements) {
+          var remove = 0;
+          for (var i = 0, len = program.statements.length; i < len; ++i) {
+            if (typeof program.statements[i] !== 'number')
+              continue;
+            if (program.statements[i] < number)
+              continue;
+            if (program.statements[i] === number) {
+              var n = i;
+              do {
+                ++n;
+                ++remove;
+              } while (n < len && typeof program.statements[n] !== 'number');
+            }
+            break;
+          }
+          var args = [i, remove, number].concat(statements);
+          program.statements.splice.apply(program.statements, args);
         }
 
         // Program = Line { Line }
diff --git a/samples/sample.unittests.txt b/samples/sample.unittests.txt
index 977943a..65d1602 100644
--- a/samples/sample.unittests.txt
+++ b/samples/sample.unittests.txt
@@ -325,8 +325,8 @@
 
 6000 PRINT : PRINT "Inline Data ";
 
-6010 DATA 1,2,3
-6011 DATA "A","B","C"
+6001 DATA 1,2,3
+6002 DATA "A","B","C"
 
 6010 T$ = "READ"
 : RESTORE
@@ -349,7 +349,7 @@
 7010 REM Test GR as part of I/O (sets cursor to window bottom)
 7010 REM ************************************************************
 
-7010 POKE 49232,0 : POKE 49234,0 : POKE 49238,0
+7011 POKE 49232,0 : POKE 49234,0 : POKE 49238,0
 
 7020 T$ = "COLOR="
 : T = 0 : U = 0 : FOR I = 0 TO 15 : COLOR= I : PLOT 0,0 : T = T + I : U = U + SCRN(0,0) : NEXT
@@ -748,9 +748,9 @@
 17040 T$ = "Sequential Access/ONERR"
 : PRINT CHR$(4)"OPEN JABBERWOCKY"
 : PRINT CHR$(4)"READ JABBERWOCKY"
-: ONERR GOTO 10742 : N = 0
+: ONERR GOTO 17042 : N = 0
 : FOR N = 0 TO 10 : INPUT A$ : NEXT
-10742 POKE 216,0 : PRINT CHR$(4)"CLOSE" : S = (N = 4) : GOSUB 1
+17042 POKE 216,0 : PRINT CHR$(4)"CLOSE" : S = (N = 4) : GOSUB 1
 
 17050 T$ = "RENAME"
 : PRINT CHR$(4)"OPEN TESTDATA"
@@ -812,8 +812,16 @@
 : T = 2
 18071 S = (T=1) AND (PEEK(222)=107) : GOSUB 1 : POKE 216,0
 
+18080 T$ = "Duplicate Lines"
+18081 T = 1
+18082 T = T + 1 : REM Should be overwritten
+18082 T = T + 1
+18083 S = (T = 2) : GOSUB 1
 
-
+18090 T$ = "Line Ordering"
+18092 T = 2
+18091 T = 1
+18093 S = (T = 2) : GOSUB 1
 
 20000 PRINT : PRINT : PRINT "Executed tests: "; TE
 20010 PRINT "Successful tests: "; TS