you can complier it to JS

Author: yjhmelody

README.md

@@ -9,7 +9,7 @@
 npm install implement-a-pl
 ```
 
-## usage
+## syntax
 ref the [example](./bin/lambda)
 
 ## API
@@ -21,12 +21,16 @@ ref the [example](./bin/lambda)
 * Environment.evalute: eval ast expression with an env
 
 
-## run
+## run the language 
 ```
 bin/lambda  demo
 ```
+## complier the language to JS
+```
+bin/code-to-js demo2
+```
 
-### example
+### example about syntax
 
 ```
 print_range = λ(a, b) if a <= b {

bin/code-to-js

@@ -0,0 +1,25 @@
+#!/usr/bin/env node
+
+let InputStream = require('../src/InputStream')
+let TokenStream = require('../src/TokenStream')
+let parser = require('../src/parser')
+let makejs = require('../src/codeGen')
+let env = require('../index')
+
+const fs = require('fs')
+
+let args = process.argv
+
+if(args.length === 2){
+    throw Error('need src and target')
+}
+else if(args.length === 3){
+    args.push('./' + args[2] + '.js')
+}
+
+code = fs.readFileSync(args[2]).toString('utf-8')
+
+ast = parser(TokenStream(InputStream(code)))
+let jsCode = makejs(ast)
+
+fs.writeFileSync(args[3], jsCode, 'utf-8')

bin/commit

@@ -1,3 +1,5 @@
+#!bash
+
 git add .
 git commit -m "auto update"
 git push

demo2

@@ -1,107 +1 @@
-# ref: http://lisperator.net/pltut/eval1/play
-
-print_range = λ(a, b) if a <= b {
-                        println(a);
-                        if a + 1 <= b {
-                          print_range(a + 1, b);
-                        } 
-                        else 
-                          println("");
-                      };
-print_range(1, 10);
-
-cons = λ(a, b) λ(f) f(a, b);
-car = λ(cell) cell(λ(a, b) a);
-cdr = λ(cell) cell(λ(a, b) b);
-NIL = λ(f) f(NIL, NIL);
-
-x = cons(1, cons(2, cons(3, cons(4, cons(5, NIL)))));
-println(car(x));                      # 1
-println(car(cdr(x)));                 # 2
-println(car(cdr(cdr(x))));            # 3
-println(car(cdr(cdr(cdr(x)))));       # 4
-println(car(cdr(cdr(cdr(cdr(x))))));  # 5
-
-
-# code = fs-readFileSync("./demo");
-# println(code);
-# println(os-arch());
-
-add = lambda(a, b){
-  1;
-# return the last expression
-  a + b
-};
-println(add(100, 133));
-
-foreach = λ(list, f)
-            if list != NIL {
-              f(car(list));
-              foreach(cdr(list), f);
-            };
-foreach(x, println);
-
-range = λ(a, b)
-          if a <= b then cons(a, range(a + 1, b))
-                    else NIL;
-
-# print the squares of 1..8
-foreach(range(1, 8), λ(x) println(x * x));
-
-
-cons = λ(x, y)
-         λ(a, i, v)
-           if a == "get"
-              then if i == 0 then x else y
-              else if i == 0 then x = v else y = v;
-
-car = λ(cell) cell("get", 0);
-cdr = λ(cell) cell("get", 1);
-set-car! = λ(cell, val) cell("set", 0, val);
-set-cdr! = λ(cell, val) cell("set", 1, val);
-
-# NIL can be a real cons this time
-NIL = cons(0, 0);
-set-car!(NIL, NIL);
-set-cdr!(NIL, NIL);
-
-## test:
-x = cons(1, 2);
-println(car(x));
-println(cdr(x));
-set-car!(x, 10);
-set-cdr!(x, 20);
-println(car(x));
-println(cdr(x));
-
-
-## IIFE
-println(let loop (n = 100)
-          if n > 0 then n + loop(n - 1)
-                   else 0);
-
-let (x = 2, y = x + 1, z = x + y)
-  println(x + y + z);
-
-# errors out, the vars are bound to the let body
-# print(x + y + z);
-
-let (x = 10) {
-  let (x = x * 2, y = x * x) {
-    println(x);  ## 20
-    println(y);  ## 400
-  };
-  println(x);  ## 10
-};
-
-fib = λ(n) if n < 2 then n else fib(n - 1) + fib(n - 2);
-println(fib(22));
-
-copyFile = lambda(source, dest){
-  writeFile(dest, readFile(source))
-};
-copyFile("demo", "demo2");
-
-
-println(1 + twice(2, 3));
-
+sum = lambda(x, y) x + y; print(sum(2, 3));

demo2.js

@@ -0,0 +1 @@
+((sum=(function (x, y) {return (x+y)})),print(sum(2,3)))

index.js

@@ -42,11 +42,12 @@ globalEnv.def("writeFile", function (k, filename, data) {
 })
 
 globalEnv.def("twice", function (k, a, b) {
-    console.log('1!!!!!', a)
+    // console.log('1!!!!!', a)
     k(a)
-    console.log('2!!!!!', b)    
+    // console.log('2!!!!!', b)
     k(b)
 })
 
 
+
 module.exports = globalEnv

src/codeGen.js

@@ -1,3 +1,9 @@
+let FALSE = {
+    type: "bool",
+    value: false
+}
+
+
 function makejs(expr) {
     return js(expr)
 
@@ -28,33 +34,67 @@ function makejs(expr) {
         }
     }
 
-    function jsAtom(expr){
+    function jsAtom(expr) {
         return JSON.stringify(expr.value)
     }
 
-    function makeVar(name){
+    function makeVar(name) {
         return name
     }
 
-    function jsVar(expr){
+    function jsVar(expr) {
         return makeVar(expr.value)
     }
 
-    function jsBinary(expr){
+    function jsBinary(expr) {
         return '(' + js(expr.left) + expr.operator + js(expr.right) + ')'
     }
 
-    function jsAssign(expr){
+    function jsAssign(expr) {
         return jsBinary(expr)
     }
 
-    function jsLambda(expr){
+    function jsLambda(expr) {
         let code = '(function '
-        if(expr.name){
+        if (expr.name) {
             code += makeVar(expr.name)
         }
         code += '(' + expr.vars.map(makeVar).join(', ') + ') {'
         code += 'return ' + js(expr.body) + '})'
         return code
     }
-}
+
+    function jsLet(expr) {
+        if (expr.vars.length === 0) {
+            return js(expr.body)
+        }
+        let iife = {
+            type: 'call',
+            func: {
+                type: 'lambda',
+                vars: [expr.vars[0].name],
+                body: {
+                    type: 'let',
+                    vars: expr.vars.slice(1),
+                    body: expr.body
+                }
+            },
+            args: [expr.vars[0].def || FALSE]
+        }
+        return '(' + js(iife) + ')'
+    }
+
+    function jsIf(expr) {
+        return '(' + js(expr.cond) + ' !== false' + '?' + js(expr.then) + ':' + js(expr.else || FALSE) + ')'
+    }
+
+    function jsProg(expr){
+        return '(' + expr.prog.map(js).join(',') + ')'
+    }
+
+    function jsCall(expr){
+        return js(expr.func) + '(' + expr.args.map(js).join(',') + ')'
+    }
+}
+
+module.exports = makejs