Candor

Experimental implementation of Candor language VM. Join #candor channel on irc.freenode.net to discuss language features.

Danger! This whole project is not stable at all, many things are broken and may/will change in future

Note: only x64 is supported now.

Language basics

Candor is essentially inspired by the ECMA-script, but has much less features and complexity (for compiler).

Functions are declared in dart-like style, variables are block scoped by default (use scope keyword for accessing outer-scope variables).

// Keywords: nil, return, scope, new, if, else, while, break

// Primitives
nil
true
false
1
'abc'
"abc"
[1, 2, 3]
{ a: 1, 'b': 2, "c": 3 }

// Variables and objects
a = 1
a.b = "abc"
a.b.c = a
a[b()][c] = x

// Functions
a() {
  return 1
}
a()

// Blocks
{
  scope a // use this to interact with variables from outer blocks
          // NOTE: the closest one will be choosed
}

// Not implemented yet

// Expr blocks
({
  a = 1
})(x)
// is equivalent to
x.a = 1

Example

factorial(x) {
  if (x == 1) return 1
  return x * factorial(x - 1)
}

factorial(10)

As you can see Candor's syntax is very close to the ecmascript's one. But there're no semicolons, statements are separated by newline symbols (whitespace is ignored).

Building

git clone git://github.com/indutny/candor.git
cd candor
make ARCH=x64 test

Status of project

Things that are implemented currently:

• Language lexer and parser
• Assigning on-stack and context variables
• Some binary operations and unary ++ and -- (both prefix and postfix) (No boolean operations so far)
• Unboxing of heap numbers (partially)
• Floating point operations (no conversion to small integers for % and &|^ so far)
• Function calls, passing arguments and using returned value
• Stop-the-world copying garbage collector
• Hash-maps (objects), numeric and string keys

Things to come:

• Finishing binary and unary operations
• String concatenation
• Functions as objects
• On-stack replacement and profile-based optimizations
• Incremental GC
• Usage in multiple-threads (aka isolates)
• Calling C++/C functions from candor
• Inline caching
• Break statement
• Better parser/lexer errors
• See TODO for more up-to-date tasks

Contributing

Any bug-fixes or feature implementations are always welcome! Only one restriction is applied to the code - it should follow Google C++ Style Guide.

Grammar (basics)

code := statement*

scope := "scope" (name ",")* name CR
block := "{" scope? statement* "}"
args := ((name ",")* name)?

array := "[" ((expr ",")* expr)? "]"
objectKv := (name|string) ":" expr
object := "{" ((objectKv ",")* objectKv)? "}"

primary := name | number | string | array | object | "(" expr ")"
member := primary ("[" expression "]" | "." name)*
callOrFun := member ("(" ((expr ",")* expr)? ")")+ |
             member "(" ((expr ",")* expr)? ")" block |
             member? "(" ((expr ",")* expr)? ")" block
assign := member "=" expr

prefix := ("!" | "--" | "++", "-", "+") expr
postfix := expr ("--" | "++")

binop1 := expr (("*" | "/") expr)*
binop2 := binop1 (("+" | "-") binop1)*
binop3 := binop2 (("&" | "|" | "^") binop2)*
binop4 := binop3 (("&&" | "||") binop3)*
binop5 := binop4 ((">" | "<" | "<=" | ">=") binop4)*
binop := binop5 (("==" | "===" | "!=" | "!==") binop5)*

blockExpr := block

return := "return" expr?
break := "break"
if := "if" "(" expr ")" block ("else" block)? |
      "if" "(" expr ")" stmt
while := "while" "(" expr ")" block

statement := (return | break | if | while | block | expr) CR

expr := binop | prefix | postfix |
        blockExpr | assign | callOrFun | member

LICENSE

Copyright (c) 2012, Fedor Indutny.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.