basic: fixes for non-line-number mode (24, 62, 81), handle unhandledrejection, MODERN default dialect, DARTMOUTH

css/ui.css

@@ -22,6 +22,12 @@
 .currentpc-marker {
   color: #ff66ee;
 }
+.currentpc-span-blocked {
+  background-color: #7e2a70;
+}
+.currentpc-marker-blocked {
+  color: #ffee33;
+}
 .tooltipbox {
     position: relative;
     display: inline-block;

package.json

@@ -55,7 +55,8 @@
     "test-worker": "NODE_PATH=$(pwd) mocha --recursive --timeout 60000 test/cli/testworker.js",
     "test-platforms": "NODE_PATH=$(pwd) mocha --recursive --timeout 60000 test/cli/testplatforms.js",
     "test-profile": "NODE_PATH=$(pwd) mocha --recursive --timeout 60000 --prof test/cli",
-    "start": "electron ."
+    "start": "electron .",
+    "fuzzbasic": "jsfuzz gen/common/basic/fuzz.js ~/basic/corpus/ --versifier false"
   },
   "main": "electron.js",
   "keywords": [

presets/basic/23match.bas

@@ -1,3 +1,5 @@
+OPTION DIALECT DEC
+0 REM from the DEC EduSystem Handbook
 100 REM***23 MATCHES
 110 LET M=23
 115 PRINT

presets/basic/craps.bas

@@ -1,5 +1,5 @@
+OPTION DIALECT HP2000
 0 REM http://www.bitsavers.org/bits/HP/paperTapes/JeffM/CRAPS.BAS
-1 OPTION DIALECT HP2000
 10  REM THIS IS A SPECIAL VERSION OF CRAPS
 20  REM 1) MAXIMUM BANK IS $1000
 30  REM 2) THE PLAYER GETS 10 CHANCES TO PLACE A BET

presets/basic/hamurabi.bas

@@ -1,3 +1,4 @@
+OPTION DIALECT ALTAIR
 10 REM *** CONVERTED FROM THE ORIGINAL FOCAL PROGRAM AND MODIFIED
 20 REM *** FOR EDUSYSTEM 70 BY DAVID AHL, DIGITAL
 30 REM *** MODIFIED FOR 8K MICROSOFT BASIC BY PETER TURNBULL

presets/basic/haunted.bas

@@ -1,4 +1,4 @@
-0 OPTION DIALECT DEC:REM http://www.bitsavers.org/bits/DEC/pdp10/games/
+OPTION DIALECT DEC:REM http://www.bitsavers.org/bits/DEC/pdp10/games/
 00001 PRINT "	This is the latest version as of 2-Jun-82."
 00005 DIM B$(30)
 00010 F=0

presets/basic/hello.bas

@@ -1,8 +1,9 @@
+OPTION DIALECT DARTMOUTH
 10 PRINT "HELLO! LET'S PROGRAM IN BASIC."
 15 PRINT
 20 INPUT "WOULD YOU MIND TYPING IN YOUR NAME";A$
 25 PRINT
-30 PRINT "THANKS, ";A$;"! THIS WILL BE FUN!";CHR$(7)
+30 PRINT "THANKS, ";A$;"! THIS WILL BE FUN!"
 35 PRINT
 40 INPUT "NOW TELL ME YOUR FAVORITE NUMBER";N
 45 PRINT

presets/basic/lander.bas

@@ -1,4 +1,4 @@
-0 OPTION DIALECT HP
+OPTION DIALECT HP
 1  REM  ****  HP BASIC PROGRAM LIBRARY  **************************
 2  REM
 3  REM        LANDER:  ROCKET LANDING VEHICLE

presets/basic/mortgage.bas

@@ -1,4 +1,4 @@
-1 OPTION DIALECT HP
+OPTION DIALECT HP
 10  PRINT "DANIEL O'ROURKE FEB. 23, 1977"
 20  PRINT "MINI-COMPUTOR 102"
 30  PRINT "SUBJECT: MORTGAGE PAYMENT"

presets/basic/sieve.bas

@@ -1,5 +1,5 @@
-001 OPTION DIALECT MODERN
+OPTION DIALECT MODERN
-002 OPTION CPUSPEED MAX
+OPTION CPUSPEED MAX
 010 REM***A PRIME NUMBER SIEVE BENCHMARK
 020 T = TIMER
 022 C = 0

presets/basic/startrader.bas

@@ -1,8 +1,8 @@
+OPTION DIALECT HP
+OPTION BASE 0:REM I GUESS HP HAS ZERO BASE???
 1 REM***STAR TRADER FROM
 2 REM***http://www.dunnington.info/public/basicgames/
 3 REM***2 chain files merged and ported to 8bitworkshop
-5 OPTION DIALECT HP
-6 OPTION BASE 0:REM I GUESS HP HAS ZERO BASE???
 10010 DIM S[12,15],T[12,12],T$[72],B[3,12]
 10020 REM COM W,D9,K9,X9,D1,X1,P9,T9,S9,Y9,H
 10030 DIM M[6,3],C[6,3]:REM COM Y1,R9,G9,Q

presets/basic/wumpus.bas

@@ -1,6 +1,6 @@
+OPTION DIALECT HP
 1 REM from: http://www.dunnington.info/public/basicgames/WUMPUS.hp
 2 REM extracted from HP library tape
-5 OPTION DIALECT HP
 10 REM- HUNT THE WUMPUS
 20 PRINT "INSTRUCTIONS (Y-N)";
 30 INPUT I$

src/codemirror/basic.js

@@ -238,7 +238,6 @@ CodeMirror.defineMode("basic", function(conf, parserConf) {
     }
 
     var external = {
-        electricChars:"dDpPtTfFeE ",
         startState: function() {
             return {
               tokenize: tokenBase,
@@ -246,8 +245,6 @@ CodeMirror.defineMode("basic", function(conf, parserConf) {
               currentIndent: 0,
               nextLineIndent: 0,
               doInCurrentLine: false
-
-
           };
         },
 

src/common/basic/compiler.ts

@@ -11,6 +11,7 @@ export interface BASICOptions {
     squareBrackets : boolean;           // "[" and "]" interchangable with "(" and ")"?
     tickComments : boolean;             // support 'comments?
     hexOctalConsts : boolean;           // support &H and &O integer constants?
+    optionalLet : boolean;              // LET is optional
     chainAssignments : boolean;         // support A = B = value (HP2000)
     validKeywords : string[];           // valid keywords (or null for accept all)
     validFunctions : string[];          // valid functions (or null for accept all)
@@ -18,7 +19,7 @@ export interface BASICOptions {
     // VALUES AND OPERATORS
     defaultValues : boolean;            // initialize unset variables to default value? (0 or "")
     stringConcat : boolean;             // can concat strings with "+" operator?
-    typeConvert : boolean;              // type convert strings <-> numbers?
+    typeConvert : boolean;              // type convert strings <-> numbers? (NOT USED)
     checkOverflow : boolean;            // check for overflow of numerics?
     bitwiseLogic : boolean;             // -1 = TRUE, 0 = FALSE, AND/OR/NOT done with bitwise ops
     maxStringLength : number;           // maximum string length in chars
@@ -390,15 +391,17 @@ export class BASICParser {
         let tok = this.consumeToken();
         switch (tok.type) {
             case TokenType.Ident:
-                if (this.opts.optionalLabels) {
+                if (this.opts.optionalLabels || tok.str == 'OPTION') {
-                    if (this.peekToken().str == ':') { // is it a label:
+                    // is it a "label :" and not a keyword like "PRINT : "
+                    if (this.peekToken().str == ':' && !this.supportsCommand(tok.str)) { 
                         this.consumeToken(); // eat the ":"
                         // fall through to the next case
                     } else {
                         this.pushbackToken(tok); // nope
                         break;
                     }
-                } else this.dialectError(`optional line numbers`);
+                } else
+                    this.dialectError(`optional line numbers`);
             case TokenType.Int:
                 this.setCurrentLabel(line, tok.str);
                 break;
@@ -406,9 +409,16 @@ export class BASICParser {
             case TokenType.Float:
                 this.compileError(`Line numbers must be positive integers.`);
                 break;
+            case TokenType.Operator:
+                if (this.supportsCommand(tok.str) && this.validKeyword(tok.str)) {
+                    this.pushbackToken(tok);
+                    break; // "?" is allowed
+                }
             default:
-                if (this.opts.optionalLabels) this.compileError(`A line must start with a line number, command, or label.`);
+                if (this.opts.optionalLabels)
-                else this.compileError(`A line must start with a line number.`);
+                    this.compileError(`A line must start with a line number, command, or label.`);
+                else
+                    this.compileError(`A line must start with a line number.`);
             case TokenType.Remark:
                 break;
         }
@@ -525,9 +535,9 @@ export class BASICParser {
     validKeyword(keyword: string) : string {
         return (this.opts.validKeywords && this.opts.validKeywords.indexOf(keyword) < 0) ? null : keyword;
     }
-    supportsKeyword(keyword: string) {
+    supportsCommand(cmd: string) : () => Statement {
-        if (this['stmt__' + keyword] != null) return true;
+        if (cmd == '?') return this.stmt__PRINT;
-        return false;
+        else return this['stmt__' + cmd];
     }
     parseStatement(): Statement | null {
         // eat extra ":" (should have separate property for this)
@@ -555,13 +565,15 @@ export class BASICParser {
                     cmd = 'GOSUB';
                 }
                 // lookup JS function for command
-                var fn = this['stmt__' + cmd];
+                var fn = this.supportsCommand(cmd);
                 if (fn) {
                     if (this.validKeyword(cmd) == null)
-                        this.dialectError(`the ${cmd} keyword`);
+                        this.dialectError(`the ${cmd} statement`);
-                    stmt = fn.bind(this)() as Statement;
+                    stmt = fn.bind(this)();
                     break;
                 } else if (this.peekToken().str == '=' || this.peekToken().str == '(') {
+                    if (!this.opts.optionalLet)
+                        this.dialectError(`assignments without a preceding LET`);
                     // 'A = expr' or 'A(X) = expr'
                     this.pushbackToken(cmdtok);
                     stmt = this.stmt__LET();
@@ -631,23 +643,22 @@ export class BASICParser {
         if (this.opts.computedGoto) {
             // parse expression, but still add to list of label targets if constant
             var expr = this.parseExpr();
-            if ((expr as Literal).value != null) {
+            if (isLiteral(expr)) this.targets[expr.value] = this.lasttoken.$loc;
-                this.targets[(expr as Literal).value] = this.lasttoken.$loc;
-            }
             return expr;
-        }
+        } else {
-        // parse a single number or ident label
+            // parse a single number or ident label
-        var tok = this.consumeToken();
+            var tok = this.consumeToken();
-        switch (tok.type) {
+            switch (tok.type) {
-            case TokenType.Ident:
+                case TokenType.Ident:
-                if (!this.opts.optionalLabels) this.dialectError(`labels other than line numbers`)
+                    if (!this.opts.optionalLabels) this.dialectError(`labels other than line numbers`)
-            case TokenType.Int:
+                case TokenType.Int:
-                var label = tok.str;
+                    var label = tok.str;
-                this.targets[label] = tok.$loc;
+                    this.targets[label] = tok.$loc;
-                return {value:label};
+                    return {value:label};
-            default:
+                default:
-                if (this.opts.optionalLabels) this.compileError(`There should be a line number or label here.`);
+                    var what = this.opts.optionalLabels ? "label or line number" : "line number";
-                else this.compileError(`There should be a line number here.`);
+                    this.compileError(`There should be a ${what} here.`);
+            }
         }
     }
     parseDatumList(): Literal[] {
@@ -841,13 +852,14 @@ export class BASICParser {
     __GO(cmd: "GOTO"|"GOSUB"): GOTO_Statement | GOSUB_Statement | ONGO_Statement {
         var expr = this.parseLabel();
         // GOTO (expr) OF (labels...)
-        if (this.opts.computedGoto && this.peekToken().str == 'OF') {
+        if (this.peekToken().str == this.validKeyword('OF')) {
             this.expectToken('OF');
             let newcmd : 'ONGOTO'|'ONGOSUB' = (cmd == 'GOTO') ? 'ONGOTO' : 'ONGOSUB';
-            return { command:newcmd, expr:expr, labels:this.parseLabelList() };
+            return { command: newcmd, expr: expr, labels: this.parseLabelList() };
+        } else {
+            // regular GOTO or GOSUB
+            return { command: cmd, label: expr };
         }
-        // regular GOTO or GOSUB
-        return { command: cmd, label: expr };
     }
     stmt__IF(): IF_Statement {
         var cond = this.parseExpr();
@@ -1100,7 +1112,8 @@ export class BASICParser {
     checkLabels() {
         for (let targ in this.targets) {
             if (this.labels[targ] == null) {
-                this.addError(`There isn't a line number ${targ}.`, this.targets[targ]);
+                var what = this.opts.optionalLabels && isNaN(parseInt(targ)) ? "label named" : "line number";
+                this.addError(`There isn't a ${what} ${targ}.`, this.targets[targ]);
             }
         }
     }
@@ -1152,6 +1165,56 @@ export const ECMA55_MINIMAL : BASICOptions = {
     arraysContainChars : false,
     endStmtRequired : true,
     chainAssignments : false,
+    optionalLet : false,
+}
+
+export const DARTMOUTH_4TH_EDITION : BASICOptions = {
+    dialectName: "DARTMOUTH4",
+    asciiOnly : true,
+    uppercaseOnly : true,
+    optionalLabels : false,
+    optionalWhitespace : false,
+    varNaming : "A1",
+    staticArrays : true,
+    sharedArrayNamespace : false,
+    defaultArrayBase : 0,
+    defaultArraySize : 11,
+    defaultValues : false,
+    stringConcat : false,
+    typeConvert : false,
+    maxDimensions : 2,
+    maxDefArgs : 255,
+    maxStringLength : 255,
+    tickComments : true,
+    hexOctalConsts : false,
+    validKeywords : [
+        'BASE','DATA','DEF','DIM','END',
+        'FOR','GO','GOSUB','GOTO','IF','INPUT','LET','NEXT','ON','OPTION','PRINT',
+        'RANDOMIZE','READ','REM','RESTORE','RETURN','STEP','STOP','SUB','THEN','TO',
+        'CHANGE','MAT','RANDOM','RESTORE$','RESTORE*',
+    ],
+    validFunctions : [
+        'ABS','ATN','COS','EXP','INT','LOG','RND','SGN','SIN','SQR','TAB','TAN',
+        'TRN','INV','DET','NUM','ZER', // NUM = # of strings input for MAT INPUT
+    ],
+    validOperators : [
+        '=', '<>', '<', '>', '<=', '>=', '+', '-', '*', '/', '^'
+    ],
+    printZoneLength : 15,
+    numericPadding : true,
+    checkOverflow : true,
+    testInitialFor : true,
+    optionalNextVar : false,
+    multipleNextVars : false,
+    bitwiseLogic : false,
+    checkOnGotoIndex : true,
+    computedGoto : false,
+    restoreWithLabel : false,
+    squareBrackets : false,
+    arraysContainChars : false,
+    endStmtRequired : true,
+    chainAssignments : true,
+    optionalLet : false,
 }
 
 // TODO: only integers supported
@@ -1191,15 +1254,15 @@ export const TINY_BASIC : BASICOptions = {
     multipleNextVars : false,
     bitwiseLogic : false,
     checkOnGotoIndex : false,
-    computedGoto : true, // TODO: is it really though?
+    computedGoto : true,
     restoreWithLabel : false,
     squareBrackets : false,
     arraysContainChars : false,
     endStmtRequired : false,
     chainAssignments : false,
+    optionalLet : false,
 }
 
-
 export const HP_TIMESHARED_BASIC : BASICOptions = {
     dialectName: "HP2000",
     asciiOnly : true,
@@ -1242,12 +1305,13 @@ export const HP_TIMESHARED_BASIC : BASICOptions = {
     multipleNextVars : false,
     bitwiseLogic : false,
     checkOnGotoIndex : false,
-    computedGoto : true,
+    computedGoto : true, // not really, but we do parse expressions for GOTO ... OF 
     restoreWithLabel : true,
     squareBrackets : true,
     arraysContainChars : true,
     endStmtRequired : true,
     chainAssignments : true,
+    optionalLet : true,
     // TODO: max line number, array index 9999
 }
 
@@ -1298,6 +1362,7 @@ export const DEC_BASIC_11 : BASICOptions = {
     arraysContainChars : false,
     endStmtRequired : false,
     chainAssignments : false,
+    optionalLet : true,
     // TODO: max line number 32767
     // TODO: \ separator, % int vars and constants, 'single' quoted
     // TODO: can't compare strings and numbers
@@ -1356,6 +1421,7 @@ export const DEC_BASIC_PLUS : BASICOptions = {
     arraysContainChars : false,
     endStmtRequired : false,
     chainAssignments : false, // TODO: can chain with "," not "="
+    optionalLet : true,
     // TODO: max line number 32767
     // TODO: \ separator, % int vars and constants, 'single' quoted
     // TODO: can't compare strings and numbers
@@ -1408,6 +1474,7 @@ export const BASICODE : BASICOptions = {
     arraysContainChars : false,
     endStmtRequired : false,
     chainAssignments : false,
+    optionalLet : true,
 }
 
 export const ALTAIR_BASIC41 : BASICOptions = {
@@ -1464,6 +1531,7 @@ export const ALTAIR_BASIC41 : BASICOptions = {
     arraysContainChars : false,
     endStmtRequired : false,
     chainAssignments : false,
+    optionalLet : true,
 }
 
 export const APPLESOFT_BASIC : BASICOptions = {
@@ -1521,6 +1589,7 @@ export const APPLESOFT_BASIC : BASICOptions = {
     arraysContainChars : false,
     endStmtRequired : false,
     chainAssignments : false,
+    optionalLet : true,
 }
 
 export const BASIC80 : BASICOptions = {
@@ -1579,6 +1648,7 @@ export const BASIC80 : BASICOptions = {
     arraysContainChars : false,
     endStmtRequired : false,
     chainAssignments : false,
+    optionalLet : true,
 }
 
 export const MODERN_BASIC : BASICOptions = {
@@ -1594,7 +1664,7 @@ export const MODERN_BASIC : BASICOptions = {
     defaultArraySize : 0, // DIM required
     defaultValues : false,
     stringConcat : true,
-    typeConvert : true,
+    typeConvert : false,
     maxDimensions : 255,
     maxDefArgs : 255,
     maxStringLength : 2048, // TODO?
@@ -1611,12 +1681,13 @@ export const MODERN_BASIC : BASICOptions = {
     multipleNextVars : true,
     bitwiseLogic : true,
     checkOnGotoIndex : true,
-    computedGoto : true,
+    computedGoto : false,
     restoreWithLabel : true,
     squareBrackets : true,
     arraysContainChars : false,
     endStmtRequired : false,
-    chainAssignments : false,
+    chainAssignments : true,
+    optionalLet : true,
 }
 
 // TODO: integer vars
@@ -1624,7 +1695,9 @@ export const MODERN_BASIC : BASICOptions = {
 // TODO: excess INPUT ignored, error msg
 
 export const DIALECTS = {
-    "DEFAULT":      ALTAIR_BASIC41,
+    "DEFAULT":      MODERN_BASIC,
+    "DARTMOUTH":    DARTMOUTH_4TH_EDITION,
+    "DARTMOUTH4":   DARTMOUTH_4TH_EDITION,
     "ALTAIR":       ALTAIR_BASIC41,
     "ALTAIR4":      ALTAIR_BASIC41,
     "ALTAIR41":     ALTAIR_BASIC41,

src/common/basic/fuzz.ts

@@ -0,0 +1,44 @@
+
+import { BASICParser, DIALECTS, BASICOptions, CompileError } from "./compiler";
+import { BASICRuntime } from "./runtime";
+import { EmuHalt } from "../emu";
+
+process.on('unhandledRejection', (reason, promise) => {
+    if (!(reason instanceof EmuHalt))
+        console.log('Unhandled Rejection at:', promise, 'reason:', reason);
+// Application specific logging, throwing an error, or other logic here
+});
+
+export function fuzz(buf) {
+    var parser = new BASICParser();
+    var str = buf.toString();
+    try {
+        var pgm = parser.parseFile(str, "test.bas");
+        var runtime = new BASICRuntime();
+        runtime.load(pgm);
+        runtime.reset();
+        runtime.print = (s) => {
+            if (s == null) throw new Error("PRINT null string");
+        }
+        runtime.input = function(prompt: string, nargs: number) : Promise<string[]> {
+            var p = new Promise<string[]>( (resolve, reject) => {
+                var arr = [];
+                for (var i=0; i<Math.random()*10; i++)
+                    arr.push(i+"");
+                resolve(arr);
+            });
+            return p;
+        }
+        for (var i=0; i<50000; i++) {
+            if (!runtime.step()) break;
+        }
+        if (Math.random() < 0.001) runtime.load(pgm);
+        for (var i=0; i<50000; i++) {
+            if (!runtime.step()) break;
+        }
+    } catch (e) {
+        if (e instanceof EmuHalt) return;
+        if (e instanceof CompileError) return;
+        throw e;
+    }
+}

src/common/basic/main.ts

@@ -1,24 +0,0 @@
-
-import { BASICParser } from "./compiler";
-
-var parser = new BASICParser();
-var readline = require('readline');
-var rl = readline.createInterface({
-    input: process.stdin,
-    output: process.stdout,
-    terminal: false
-});
-rl.on('line', function (line) {
-    parser.tokenize(line);
-    console.log(parser.tokens);
-    try {
-        var ast = parser.parse();
-        console.log(JSON.stringify(ast, null, 4));
-    } catch (e) {
-        console.log(e);
-    }
-    if (parser.errors.length) {
-        console.log(parser.errors);
-        parser.errors = [];
-    }
-})

src/common/basic/run.ts

@@ -21,14 +21,22 @@ var fs = require('fs');
 var parser = new BASICParser();
 var runtime = new BASICRuntime();
 
+function getCurrentLabel() {
+    var loc = runtime.getCurrentSourceLocation();
+    return loc ? loc.label : "?";
+}
+
 // parse args
 var filename = '/dev/stdin';
 var args = process.argv.slice(2);
+var force = false;
 for (var i=0; i<args.length; i++) {
     if (args[i] == '-v')
         runtime.trace = true;
     else if (args[i] == '-d')
         parser.opts = DIALECTS[args[++i]] || Error('no such dialect');
+    else if (args[i] == '-f')
+        force = true;
     else if (args[i] == '--dialects')
         dumpDialectInfo();
     else
@@ -45,13 +53,13 @@ try {
         console.log(`@@@ ${e}`);
 }
 parser.errors.forEach((err) => console.log(`@@@ ${err.msg} (line ${err.label})`));
-if (parser.errors.length) process.exit(2);
+if (parser.errors.length && !force) process.exit(2);
 
 // run program
 try {
     runtime.load(pgm);
 } catch (e) {
-    console.log(`### ${e.message} (line ${runtime.getCurrentSourceLocation().label})`);
+    console.log(`### ${e.message} (line ${getCurrentLabel()})`);
     process.exit(1);
 }
 runtime.reset();
@@ -86,7 +94,7 @@ runtime.resume = function() {
                 process.exit(0);
             }
         } catch (e) {
-            console.log(`### ${e.message} (line ${runtime.getCurrentSourceLocation().label})`);
+            console.log(`### ${e.message} (line ${getCurrentLabel()})`);
             process.exit(1);
         }
     });
@@ -98,7 +106,7 @@ runtime.resume();
 function dumpDialectInfo() {
     var dialects = new Set<BASICOptions>();
     var array = {};
-    var SELECTED_DIALECTS = ['TINY','ECMA55','HP','DEC','ALTAIR','BASIC80','MODERN'];
+    var SELECTED_DIALECTS = ['TINY','ECMA55','DARTMOUTH','HP','DEC','ALTAIR','BASIC80','MODERN'];
     SELECTED_DIALECTS.forEach((dkey) => {
         dialects.add(DIALECTS[dkey]);
     });
@@ -121,7 +129,7 @@ function dumpDialectInfo() {
     });
     dialects.forEach((dialect) => {
         ALL_KEYWORDS.forEach((keyword) => {
-            if (parser.supportsKeyword(keyword)) {
+            if (parser.supportsCommand(keyword)) {
                 var has = dialect.validKeywords == null || dialect.validKeywords.indexOf(keyword) >= 0;
                 keyword = '`'+keyword+'`'
                 if (!array[keyword]) array[keyword] = [];

src/common/basic/runtime.ts

@@ -473,7 +473,7 @@ export class BASICRuntime {
             this.runtimeError(`I can't call a function here.`);
         // is it a subscript?
         if (expr.args) {
-            // set array slice (HP BASIC)
+            // TODO: set array slice (HP BASIC)
             if (this.opts.arraysContainChars && expr.name.endsWith('$')) {
                 this.runtimeError(`I can't set array slices via this command yet.`);
             } else {
@@ -566,8 +566,8 @@ export class BASICRuntime {
     // converts a variable to string/number based on var name
     assign(name: string, right: number|string, isRead?:boolean) : number|string {
         // convert data? READ always converts if read into string
-        if (this.opts.typeConvert || (isRead && name.endsWith("$")))
+        if (isRead && name.endsWith("$"))
-            return this.convert(name, right);
+            return this.checkValue(this.convert(name, right), name);
         // TODO: use options
         if (name.endsWith("$")) {
             return this.convertToString(right, name);
@@ -604,9 +604,9 @@ export class BASICRuntime {
             if (this.opts.staticArrays) return;
             else this.runtimeError(`I already dimensioned this array (${name}) earlier.`)
         }
-        if (this.getTotalArrayLength(dims) > this.opts.maxArrayElements) {
+        var total = this.getTotalArrayLength(dims);
+        if (total > this.opts.maxArrayElements)
             this.runtimeError(`I can't create an array with this many elements.`);
-        }
         var isstring = name.endsWith('$');
         // if numeric value, we use Float64Array which inits to 0
         var arrcons = isstring ? Array : Float64Array;
@@ -635,7 +635,7 @@ export class BASICRuntime {
     getArray(name: string, order: number) : [] {
         if (!this.arrays[name]) {
             if (this.opts.defaultArraySize == 0)
-                this.dialectError(`automatically declare arrays without a DIM statement`);
+                this.dialectError(`automatically declare arrays without a DIM statement (or did you mean to call a function?)`);
             if (order == 1)
                 this.dimArray(name, this.opts.defaultArraySize-1);
             else if (order == 2)
@@ -648,7 +648,7 @@ export class BASICRuntime {
 
     arrayGet(name: string, ...indices: number[]) : basic.Value {
         var arr = this.getArray(name, indices.length);
-        indices = indices.map(Math.round);
+        indices = indices.map(this.ROUND.bind(this));
         var v = arr;
         for (var i=0; i<indices.length; i++) {
             var idx = indices[i];
@@ -668,10 +668,20 @@ export class BASICRuntime {
     // for HP BASIC string slicing (TODO?)
     modifyStringSlice(orig: string, add: string, start: number, end: number) : string {
         orig = orig || "";
-        return (orig + ' '.repeat(start)).substr(0, start-1) + add + orig.substr(end);
+        this.checkString(orig);
+        this.checkString(add);
+        if (!end) end = start;
+        start = this.ROUND(start);
+        end = this.ROUND(end);
+        if (start < 1 || end < 1) this.dialectError(`accept a string slice index less than 1`);
+        return (orig + ' '.repeat(start)).substr(0, start-1) + add.substr(0, end+1-start) + orig.substr(end);
     }
+
     getStringSlice(s: string, start: number, end: number) {
         s = this.checkString(s);
+        start = this.ROUND(start);
+        end = this.ROUND(end);
+        if (start < 1 || end < 1) this.dialectError(`accept a string slice index less than 1`);
         return s.substr(start-1, end+1-start);
     }
 
@@ -707,7 +717,8 @@ export class BASICRuntime {
         var s = '';
         for (var arg of stmt.args) {
             var expr = this.expr2js(arg);
-            s += `this.printExpr(${expr});`;
+            var name = (expr as any).name;
+            s += `this.printExpr(this.checkValue(${expr}, ${JSON.stringify(name)}));`;
         }
         return s;
     }
@@ -751,7 +762,7 @@ export class BASICRuntime {
             if (this.opts.arraysContainChars && lexpr.args && lexpr.name.endsWith('$')) {
                 s += `this.vars.${lexpr.name} = this.modifyStringSlice(this.vars.${lexpr.name}, _right, `
                 s += lexpr.args.map((arg) => this.expr2js(arg)).join(', ');
-                s += ')';
+                s += ');';
             } else {
                 var ljs = this.assign2js(lexpr);
                 s += `${ljs} = this.assign(${JSON.stringify(lexpr.name)}, _right);`;
@@ -956,7 +967,7 @@ export class BASICRuntime {
                 return exprname.endsWith("$") ? "" : 0;
             }
             if (exprname != null && obj == null) {
-                this.runtimeError(`I haven't set a value for ${exprname}.`);
+                this.runtimeError(`I haven't assigned a value to ${exprname}.`);
             } else if (exprname != null) {
                 this.runtimeError(`I got an invalid value for ${exprname}: ${obj}`);
             } else {
@@ -1193,7 +1204,7 @@ export class BASICRuntime {
         len = this.ROUND(len);
         if (len <= 0) return '';
         if (len > this.opts.maxStringLength)
-            this.runtimeError(`I can't create a string longer than ${this.opts.maxStringLength} characters.`);
+            this.dialectError(`create a string longer than ${this.opts.maxStringLength} characters`);
         if (typeof chr === 'string')
             return chr.substr(0,1).repeat(len);
         else

src/ide/ui.ts

@@ -1901,7 +1901,8 @@ function globalErrorHandler(msgevent) {
   if (msg.indexOf("QuotaExceededError") >= 0) {
     requestPersistPermission(false, false);
   } else {
-    var err = msgevent.error;
+    var err = msgevent.error || msgevent.reason;
+    msg = err.message || msg;
     showExceptionAsError(err, msg);
   }
 }
@@ -1909,10 +1910,12 @@ function globalErrorHandler(msgevent) {
 // catch errors
 function installErrorHandler() {
   window.addEventListener('error', globalErrorHandler);
+  window.addEventListener('unhandledrejection', globalErrorHandler);
 }
   
 function uninstallErrorHandler() {
   window.removeEventListener('error', globalErrorHandler);
+  window.removeEventListener('unhandledrejection', globalErrorHandler);
 }
 
 function gotoNewLocation(replaceHistory? : boolean) {

src/ide/views.ts

@@ -329,10 +329,12 @@ export class SourceEditor implements ProjectView {
   }
 
   setCurrentLine(line:SourceLocation, moveCursor:boolean) {
+    var blocked = platform.isBlocked && platform.isBlocked();
 
     var addCurrentMarker = (line:SourceLocation) => {
       var div = document.createElement("div");
-      div.classList.add('currentpc-marker');
+      var cls = blocked ? 'currentpc-marker-blocked' : 'currentpc-marker';
+      div.classList.add(cls);
       div.appendChild(document.createTextNode("\u25b6"));
       this.editor.setGutterMarker(line.line-1, "gutter-info", div);
     }
@@ -343,7 +345,8 @@ export class SourceEditor implements ProjectView {
       if (moveCursor) {
         this.editor.setCursor({line:line.line-1,ch:line.start||0}, {scroll:true});
       }
-      var markOpts = {className:'currentpc-span', inclusiveLeft:true};
+      var cls = blocked ? 'currentpc-span-blocked' : 'currentpc-span';
+      var markOpts = {className:cls, inclusiveLeft:true};
       if (line.start || line.end)
         this.markCurrentPC = this.editor.markText({line:line.line-1,ch:line.start}, {line:line.line-1,ch:line.end||line.start+1}, markOpts);
       else
@@ -379,7 +382,7 @@ export class SourceEditor implements ProjectView {
 
   refreshDebugState(moveCursor:boolean) {
     // TODO: only if line changed
-    // TODO: remove after compilation restarts platform
+    // TODO: remove after compilation
     this.clearCurrentLine(moveCursor);
     var line = this.getActiveLine();
     if (line) {

src/platform/basic.ts

@@ -125,14 +125,14 @@ class BASICPlatform implements Platform {
         // TODO: only hot reload when we hit a label?
         var didExit = this.runtime.exited;
         this.program = data;
-        this.runtime.load(data);
+        var resumePC = this.runtime.load(data);
         this.tty.uppercaseOnly = true; // this.program.opts.uppercaseOnly; //TODO?
         // map editor to uppercase-only if need be
         views.textMapFunctions.input = this.program.opts.uppercaseOnly ? (s) => s.toUpperCase() : null;
         // HP 2000 has cute lil small caps (TODO: messes up grid alignment tho)
         //this.tty.page.style.fontVariant = (this.program.opts.dialectName == 'HP2000') ? 'small-caps' : 'normal';
         // only reset if we exited, or couldn't restart at label (PC reset to 0)
-        if (!this.hotReload || didExit || this.runtime.curpc == 0)
+        if (!this.hotReload || didExit || !resumePC)
             this.reset();
     }
 
@@ -156,7 +156,7 @@ class BASICPlatform implements Platform {
         this.timer.start();
     }
 
-    isBlocked() { return this.tty.waitingfor != null; } // is blocked for input?
+    isBlocked() { return this.tty.waitingfor != null || this.runtime.exited; } // is blocked for input?
     isRunning() { return this.timer.isRunning(); }
     getDefaultExtension() { return ".bas"; }
     getToolForFilename() { return "basic"; }