mirror of
https://github.com/samsonjs/elisp.js.git
synced 2026-03-25 09:15:49 +00:00
hooked up defvar, defun, set, and setq.
This commit is contained in:
Sami Samhuri
parent
6fe9048c6e
commit
df628aa959
1 changed files with 116 additions and 68 deletions
184
el.js
184
el.js
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@ -1,4 +1,4 @@
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var EL = function(){};
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var spidermonkeykludge = 0;
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// spidermonkey doesn't like a C-style comment at the beginning
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/*
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@ -38,6 +38,10 @@ Array.prototype.each = function(fn) {
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}
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};
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// our namespace
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var EL = function(){};
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/****************************************************************
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**** Parser ****************************************************
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@ -188,48 +192,39 @@ EL.Parser.prototype.lookingAtNumber = function() {
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};
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EL.Parser.prototype.lookingAtCons = function() {
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this.fake = true;
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var orig_pos = this.pos,
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_ = this.consumeChar(),
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_ = this.parseExpression(),
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cdr = this.parseExpression();
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this.pos = orig_pos; // rewind, like it never happened.
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this.fake = false;
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return cdr != null && EL.tag(cdr) == 'symbol' && EL.val(cdr) == '.';
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return EL.typeOf(cdr) == 'array' && EL.tag(cdr) == 'symbol' && EL.val(cdr) == '.';
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};
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EL.Parser.prototype.parseExpression = function() {
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var value,
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c = this.peek();
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if (c == '(' && this.lookingAtCons()) {
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// print("CONS(");
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value = ['cons', this.parseCons()];
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}
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else if (c == '(') {
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// print("LIST(");
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var list = this.parseList();
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value = (list.length > 0) ? ['list', list] : EL.nil;
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}
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else if (c == ')') {
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// print(">>> ) <<<");
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return this.consumeChar();
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}
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else if (c == "'") {
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// print("QUOTE");
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this.consumeChar();
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value = ['list', [['symbol', 'quote']]];
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value[1].push(this.parseExpression());
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}
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else if (c == '"') {
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// print("STRING");
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value = ['string', this.parseString()];
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}
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else if (this.lookingAtNumber()) {
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// print("NUMBER");
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value = ['number', this.parseNumber()];
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}
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else if (c) {
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// print("SYMBOL");
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value = ['symbol', this.parseSymbol()];
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}
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this.consumeWhitespace();
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@ -250,20 +245,24 @@ EL.SymbolTable = function(bindings) {
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if (bindings) this.define(bindings);
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};
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EL.SymbolTable.prototype.lookup = function(name) {
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EL.SymbolTable.prototype.lookupWithScope = function(name) {
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var i = this.level,
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symbol;
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while (i >= 0) {
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// print('*** looking for ' + name + ' at level ' + i);
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symbol = this.symbols[i][name];
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if (symbol) {
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return symbol;
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value = this.symbols[i][name];
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if (value) {
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return [i, value];
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}
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--i;
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}
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return null;
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};
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EL.SymbolTable.prototype.lookup = function(name) {
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var pair = this.lookupWithScope(name);
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return pair && pair[1];
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};
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// store the given symbol/value pair in the symbol table at the current level.
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EL.SymbolTable.prototype.define = function(name, value) {
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if (value === undefined && EL.typeOf(name) == 'array') {
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@ -274,17 +273,21 @@ EL.SymbolTable.prototype.define = function(name, value) {
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while (i < n) {
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var name = bindings[i][0],
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value = bindings[i][1];
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// print('name: ' + name);
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// print('value: ' + value);
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scope[name] = value;
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++i;
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}
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}
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else {
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// print('defining ' + name + ' = ' + value + ' at level ' + this.level);
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this.symbols[this.level][name] = value;
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}
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};
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EL.SymbolTable.prototype.pushScope = function(bindings) {
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// print('>>> pushing scope <<<');
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// print('>>> level going from ' + this.level + ' to ' + (1+this.level));
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// print(bindings);
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this.symbols[++this.level] = [];
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if (bindings) this.define(bindings);
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};
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@ -293,6 +296,12 @@ EL.SymbolTable.prototype.popScope = function() {
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--this.level;
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};
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EL.SymbolTable.prototype.set = function(name, value) {
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var pair = this.lookupWithScope(name),
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level = pair[0];
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this.symbols[level][name] = value;
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};
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/****************************************************************
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****************************************************************/
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@ -317,16 +326,6 @@ EL.PrimitiveVariables = [
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// this is bound to the EL.Evaluator object
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EL.PrimitiveFunctions = [
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['defvar', {
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type: 'primitive',
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name: 'defvar',
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params: ['symbol', 'value', 'docstring'],
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body: function(symbol, value, docstring) {
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this.defineVar(EL.symbolName(symbol), value, docstring);
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return EL.nil;
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},
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docstring: "define a variable in the local scope"
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}],
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['+', {
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type: 'primitive',
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name: '+',
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@ -386,7 +385,7 @@ EL.PrimitiveFunctions = [
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else print(s);
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}
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if (tag == 'number' || tag == 'symbol' || tag == 'string') {
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p(El.val(x));
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p(EL.val(x));
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}
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else if (tag == 'function') {
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var fn = EL.val(x);
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@ -481,33 +480,39 @@ EL.Evaluator.prototype.defineVar = function(symbol, value, docstring) {
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});
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};
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EL.Evaluator.prototype.setVar = function(symbol, value) {
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var valueObject = this.lookupVar(symbol);
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valueObject.value = value;
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this.variables.set(symbol, valueObject);
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};
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EL.Evaluator.prototype.defineFunc = function(symbol, params, body, docstring) {
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this.functions.define(symbol, {
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type: 'function',
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name: symbol,
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params: params,
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params: EL.val(params),
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body: body,
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docstring: docstring || "(undocumented)"
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});
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};
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EL.Evaluator.prototype.bind = function(params, args) {
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var self = this;
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return ;
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};
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EL.Evaluator.prototype.call = function(func, args) {
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//var bindings = this.bind(func.params, args);
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print('calling ' + func.name + ' with args: ' + args);
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var result;
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if (func.type === 'primitive') {
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result = func.body.apply(this, args);
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}
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else {
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this.functions.pushScope();
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this.variables.pushScope(func.params.map(function(e, i){
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return [e, args[i]];
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var name = EL.symbolName(e),
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value = {
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type: 'variable',
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value: this.eval(args[i])
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};
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return [name, value];
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}));
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result = this.evalExpressions(func.body);
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this.functions.popScope();
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this.variables.popScope();
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}
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return result;
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@ -529,9 +534,59 @@ EL.Evaluator.prototype.eval = function(expr) {
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// var cons = expr[1];
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// result = [this.eval(cons[0]), this.eval(cons[1])];
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// }
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///////////////////
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// special forms //
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///////////////////
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// (many could be in lisp when there are macros) //
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else if (EL.isQuote(expr)) {
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result = EL.cdr(EL.val(expr));
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result = EL.val(EL.val(expr));
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}
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else if (EL.isDefVar(expr)) {
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var val = EL.val(expr),
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name = EL.symbolName(val[1]),
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value = this.eval(val[2]),
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docstring = val[3];
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// TODO check for re-definitions
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this.defineVar(name, value, docstring);
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result = EL.nil;
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}
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else if (EL.isDefFunc(expr)) {
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var val = EL.val(expr),
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name = EL.symbolName(val[1]),
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params = val[2],
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docstring = EL.isString(val[3]) && val[3],
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body = val.slice(docstring ? 4 : 3);
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// TODO check for re-definitions
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this.defineFunc(name, params, body, docstring);
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result = EL.nil;
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}
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else if (EL.isSet(expr)) {
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var val = EL.val(expr),
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name = EL.symbolName(val[1]),
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value = this.eval(val[2]);
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result = this.setVar(name, value);
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}
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else if (EL.isSetq(expr)) {
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var val = EL.val(expr),
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i = 0;
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while (EL.isSymbol(val[i+1])) {
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var name = EL.symbolName(val[i+1]),
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value = this.eval(val[i+2]);
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result = this.setVar(name, value);
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i += 2;
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}
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}
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else if (EL.isIf(expr)) {
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var val = EL.val(expr),
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condition = this.eval(val[1]),
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trueBlock = val[2],
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nilBlock = val[3];
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result = this.primitiveIf(condition, trueBlock, nilBlock);
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}
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// function application
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else if (EL.tag(expr) == 'list') {
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var list = expr[1],
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car = list[0],
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@ -590,28 +645,18 @@ EL.assert = function(condition, message) {
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};
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EL.tag = function(expr) {
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EL.assert(function() { 'tag'; return EL.typeOf(expr) == 'array'; }, expr);
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EL.assert(function() { var f='tag'; return EL.typeOf(expr) == 'array'; }, expr);
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return expr[0];
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};
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EL.val = function(expr) {
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EL.assert(function() { 'val'; return EL.typeOf(expr) == 'array'; }, expr);
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EL.assert(function() { var f='val'; return EL.typeOf(expr) == 'array'; }, expr);
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return expr[1];
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};
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EL.car = function(cons) {
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EL.assert(function(){ 'car'; return EL.typeOf(cons) == 'array'; }, cons);
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return cons[0];
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};
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EL.cdr = function(cons) {
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EL.assert(function(){ 'cdr'; return EL.typeOf(cons) == 'array'; }, cons);
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return cons.slice(1);
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};
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EL.symbolName = function(symbol) {
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// EL.Util.pp(symbol);
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EL.assert(function(){ 'symbolName'; return EL.isSymbol(symbol); }, symbol);
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EL.assert(function(){ var f='symbolName'; return EL.isSymbol(symbol); }, symbol);
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return symbol[1];
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};
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@ -626,7 +671,6 @@ EL.isString = function(expr) {
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EL.isList = function(expr) {
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return (EL.tag(expr) == 'list');
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};
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EL.isCons = EL.isList;
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EL.isFunction = function(expr) {
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return (EL.tag(expr) == 'function');
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@ -639,7 +683,7 @@ EL.isAtom = function(expr) {
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EL.inferType = function(exprs) {
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var type = 'number',
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initial = 0,
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i = exprs.length;
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i = exprs.length-1;
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while(i >= 0) {
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if (EL.isString(exprs[i--])) {
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type = 'string';
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@ -650,13 +694,19 @@ EL.inferType = function(exprs) {
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return [type, initial];
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};
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EL.isQuote = function(expr) {
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EL.isSpecialForm = function(name, expr) {
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var tag = EL.tag(expr),
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val = EL.val(expr),
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car = EL.isCons(val) && EL.car(val),
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name = car && EL.symbolName(car);
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return (tag == 'list' && name == 'quote');
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car = EL.typeOf(expr) == 'array' && EL.val(expr)[0],
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thisName = car && EL.symbolName(car);
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return (tag == 'list' && thisName == name);
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};
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EL.isQuote = function(expr){return EL.isSpecialForm('quote', expr);};
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EL.isDefVar = function(expr){return EL.isSpecialForm('defvar', expr);};
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EL.isDefFunc = function(expr){return EL.isSpecialForm('defun', expr);};
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EL.isSet = function(expr){return EL.isSpecialForm('set', expr);};
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EL.isSetq = function(expr){return EL.isSpecialForm('setq', expr);};
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EL.isCond = function(expr){return EL.isSpecialForm('cond', expr);};
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EL.isIf = function(expr){return EL.isSpecialForm('if', expr);};
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EL.eval = function(exprs) {
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var e = new EL.Evaluator();
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@ -673,10 +723,6 @@ EL.parseOne = function(string) {
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};
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EL.read = EL.parseOne;
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EL.print = function(expr) {
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EL.Util.pp(expr);
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};
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EL.rep = function(string) {
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EL.print(EL.eval(EL.read(string)));
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};
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@ -686,8 +732,7 @@ EL.repl = function() {
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e = new EL.Evaluator();
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while (true) {
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print("elisp> ");
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var x = readline();
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EL.print(e.eval(p.parseOne(x)));
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EL.print(e.eval(p.parseOne(readline())));
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}
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};
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@ -784,9 +829,13 @@ EL.Util.pp = function(x, indent, key, noprint) {
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printB(space + '"' + x + '"');
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}
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return buffer;
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break;
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case 'array':
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// nil special case
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if (x.length == 2 && EL.tag(x) == 'symbol' && EL.val(x) == 'nil') {
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return EL.Util.pp(null, indent, key);
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}
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if (key) {
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printB(space + key + ': [');
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}
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@ -809,7 +858,6 @@ EL.Util.pp = function(x, indent, key, noprint) {
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printB(space + '(null)');
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}
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return buffer;
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break;
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default:
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if (key) {
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@ -819,12 +867,12 @@ EL.Util.pp = function(x, indent, key, noprint) {
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printB(space + x);
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}
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return buffer;
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break;
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}
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var s = buffer;
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if (!noprint) dumpBuffer();
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return s;
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};
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EL.print = EL.Util.pp;
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// spidermonkey doesn't like a C-style comment at the end either
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function spidermonkeyissilly(){};
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spidermonkeykludge = 1;
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