bind expression (:=) instead of let

examples/bf.monkey

@@ -1,7 +1,7 @@
 #!./monkey-lang
 
-let fill = fn(x, i) {
-  let xs = []
+fill := fn(x, i) {
+  xs := []
   while (i > 0) {
     xs = push(xs, x)
     i = i - 1
@@ -9,17 +9,17 @@ let fill = fn(x, i) {
   return xs
 }
 
-let buildJumpMap = fn(program) {
-  let stack = []
-  let map = {}
+buildJumpMap := fn(program) {
+  stack := []
+  map := {}
 
-  let n = 0
+  n := 0
   while (n < len(program)) {
     if (program[n] == "[") {
       stack = push(stack, n)
     }
     if (program[n] == "]") {
-      let start = pop(stack)
+      start := pop(stack)
       map[start] = n
       map[n] = start
     }
@@ -29,13 +29,13 @@ let buildJumpMap = fn(program) {
   return map
 }
 
-let ascii_table = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
+ascii_table := "\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
 
-let ord = fn(s) {
+ord := fn(s) {
   return ascii_table[s]
 }
 
-let chr = fn(x) {
+chr := fn(x) {
   if (x < 0) {
     return "??"
   }
@@ -45,27 +45,27 @@ let chr = fn(x) {
   return ascii_table[x]
 }
 
-let read = fn() {
-  let buf = input()
+read := fn() {
+  buf := input()
   if (len(buf) > 0) {
     return ord(buf[0])
   }
   return 0
 }
 
-let write = fn(x) {
+write := fn(x) {
   print(chr(x))
 }
 
-let VM = fn(program) {
-  let jumps = buildJumpMap(program)
+VM := fn(program) {
+  jumps := buildJumpMap(program)
 
-  let ip = 0
-  let dp = 0
-  let memory = fill(0, 32)
+  ip := 0
+  dp := 0
+  memory := fill(0, 32)
 
   while (ip < len(program)) {
-    let op = program[ip]
+    op := program[ip]
 
     if (op == ">") {
       dp = dp + 1
@@ -108,9 +108,9 @@ let VM = fn(program) {
 }
 
 // Hello World
-let program = "++++++++ [ >++++ [ >++ >+++ >+++ >+ <<<<- ] >+ >+ >- >>+ [<] <- ] >>.  >---.  +++++++..+++.  >>.  <-.  <.  +++.------.--------.  >>+.  >++."
+program := "++++++++ [ >++++ [ >++ >+++ >+++ >+ <<<<- ] >+ >+ >- >>+ [<] <- ] >>.  >---.  +++++++..+++.  >>.  <-.  <.  +++.------.--------.  >>+.  >++."
 
 // 2 + 5
-// let program = "++> +++++ [<+>-] ++++++++ [<++++++>-] < ."
+// program := "++> +++++ [<+>-] ++++++++ [<++++++>-] < ."
 
 VM(program)

examples/demo.monkey

@@ -1,21 +1,21 @@
-let name = "Monkey";
-let age = 1;
-let inspirations = ["Scheme", "Lisp", "JavaScript", "Clojure"];
-let book = {
+name := "Monkey";
+age := 1;
+inspirations := ["Scheme", "Lisp", "JavaScript", "Clojure"];
+book := {
   "title": "Writing A Compiler In Go",
   "author": "Thorsten Ball",
   "prequel": "Writing An Interpreter In Go"
 };
 
-let printBookName = fn(book) {
-    let title = book["title"];
-    let author = book["author"];
+printBookName := fn(book) {
+    title := book["title"];
+    author := book["author"];
     print(author + " - " + title);
 };
 
 printBookName(book);
 
-let fibonacci = fn(x) {
+fibonacci := fn(x) {
   if (x == 0) {
     return 0
   } else {
@@ -27,8 +27,8 @@ let fibonacci = fn(x) {
   }
 };
 
-let map = fn(arr, f) {
-  let iter = fn(arr, accumulated) {
+map := fn(arr, f) {
+  iter := fn(arr, accumulated) {
     if (len(arr) == 0) {
       return accumulated
     } else {
@@ -39,5 +39,5 @@ let map = fn(arr, f) {
   return iter(arr, []);
 };
 
-let numbers = [1, 1 + 1, 4 - 1, 2 * 2, 2 + 3, 12 / 2];
+numbers := [1, 1 + 1, 4 - 1, 2 * 2, 2 + 3, 12 / 2];
 map(numbers, fibonacci);

examples/fact.monkey

@@ -1,4 +1,4 @@
-let fact = fn(n) {
+fact := fn(n) {
   if (n == 0) {
     return 1
   }

examples/factt.monkey

@@ -1,4 +1,4 @@
-	let fact = fn(n, a) {
+fact := fn(n, a) {
   if (n == 0) {
     return a
   }

examples/fib.monkey

@@ -1,4 +1,4 @@
-let fib = fn(x) {
+fib := fn(x) {
   if (x == 0) {
     return 0
   }

examples/fibi.monkey

@@ -1,11 +1,11 @@
-let fib = fn(n) {
+fib := fn(n) {
    if (n < 3) {
      return 1
    }
-   let a = 1
-   let b = 1
-   let c = 0
-   let i = 0
+   a := 1
+   b := 1
+   c := 0
+   i := 0
    while (i < n - 2) {
      c = a + b
      b = a

examples/fibt.monkey

@@ -1,4 +1,4 @@
-let fib = fn(n, a, b) {
+fib := fn(n, a, b) {
   if (n == 0) {
     return a
   }

examples/input.monkey

@@ -1,3 +1,3 @@
-let name = input("What is your name? ")
+name := input("What is your name? ")
 
 print("Hello " + name)

examples/selectors.monkey

@@ -1,5 +0,0 @@
-let d = {"foo": 1, "bar": 2}
-
-assert(d.foo == 1, "d.foo != 1")
-assert(d.bar == 2, "d.bar != 2")
-assert(d.bogus == null, "d.bogus != null")