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Mutan
Mutan is a C-Like language for the Ethereum project. Mutan supports a full, statically typed higher level language that compiles to native Ethereum Assembler. Repo will be moved.
An online editor and compiler can be found here
The syntax is specified using Extended Backus-Naur Form (EBNF):
digit excluding zero = "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
digit = "0" | digit excluding zero ;
The following keywords are reserved and may not be used at identifiers
this if else return exit for asm nil transact create call
Mutan contains the following operators and delimiters (some are wip)
+ = | ( )
- == & { }
* >= ++ ;
/ <= --
Numeric types in Mutan can only be represented by integer values and are architecture-independent. They are all represented in big endian byte order. Signed integers aren't supported (yet?)
int8 the set of all _unsigned_ integers (0 to 255)
int16 the set of all _unsigned_ integers (0 to 65535)
int32 the set of all _unsigned_ integers (0 to 4294967295)
int64 the set of all _unsigned_ integers (0 to 18446744073709551615)
int256 the set of all _unsigned_ integers (0 to 1.1579209e+77)
big same as int256
Numbers may be specified in decimal and hexadecimal format.
Arrays are of theoretical unlimited length
ArrayType = ElementType "[" Number "]" .
ElementType = Type .
The following are all valid arrays:
int16[10] a
int32[10] b
big[10] c
A declaration binds a identifier to a type. Every identifier must be declared. No identifier may be declared twice. All declarations are global (for now, TODO/FIXME).
Declaration = TypeDecl .
Mutan, in it's current state, is globally scoped: 1. No identifier may be used twice 2. All identifiers must be declared using a Type
Types:
int int8 int16 int32 int64 int256 big
(todo)
bool string
Statement = Declaration | Block | IfStmt | ForStmt | Expression
Expression = Ptr | Number | Hex | Identifier .
Ptr = Identifier | "nil" .
Number = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" .
Hex = "0x" "a" | "b" | "c" | "d" | "e" | Number .
Identifier = * .
Blocks contain, but not necessarily, contain lists of Statements within matching brackets.
Block = "{" StatementList "}" .
StatementList = { Statement ";" } .
If statements specify the conditional execution of two branches according to the value of an expression. If the expression evaluated to true, the "if" branch is executed, else, if present, the else branch is executed.
IfStmt = "if" [ SimpleStmt ";" ] Expression Block [ "else" Block ] .
if x < 10 {
x = maximum
}
The expression may be preceded by a simple statement which executes before the boolean expression
if int8 x = this.Value(); x < 10 {
x = maximum
} else {
y = 10
}
A "for" statements specifies repeated execution of a block, the iteration is controlled by a conditional block.
ForStmt = "for" [ InitStmt ] ";" [ Condition ] ";" [ PostStmt ] .
InitStmt = SimpleStmt .
PostStmt = SimpleStmt .
A "for" in it's simplest form is a C-Like "while" statement (therefor Mutan doesn't have a "while")
for a < b {
a = a * 2
}
A "for" statement in it's purest form is controlled my a initialiser, condition and a post statement which will be executed at the end of the Block
for int8 = 0; a < b; a++ {
b = b - 1
}
for cond { T() } is the same as for ; cond ; { T() }
for cond; post { T() } is the same as for ; cond; post { T() }
Mutan comes with a couple build in functions for stopping, creating and transacting between multiple objects and context functions.
"exit()"
Stops the execution of the current call
Success = "call(" Expression, Expression, Expression, Ptr, Ptr ")"
Calls contract specified by the address and executes. Arguments can be passed to the in
argument and the return value can be specified by the out
parameters. Return a 1
or 0
depending whether this call was success or not.
Success = "transact(" Expression, Expression, Ptr ")"
Handles a transaction between two objects.
Address = "create(" Expression, Expression ")"
Creates a new contract given by script
and returns the Address
of the transaction.
The following functions relate to the current executing context (i.e. the closure). These build-in functions are prefixed with this.
.
Method = "this" Dot MethodName "(" [ Expression ] ")" .
Dot = "." .
MethodName = "dataLoad" | "dataSize" | "origin" | "caller" | "gasPrice" | "value" |
"diff" | "prevHash" | "time" | "gasPrice" | "number" | "coinbase" | "gas" .
data Returns the x'th value of the attached data of this call
dataSize Returns the size of the data attached to this call
origin Returns the origin address of this execution
caller Returns the current caller of the closure
gasPrice Returns the gas price attached to this call
value Returns the value attached to this call
balance Returns the value of the current call
diff Returns the current difficulty
prevHash Returns the previous block's hash
time Returns the current block's timestamp
gasPrice Returns the attached call's gas price
number Returns the current block's number
coinbase Returns the current block's coinbase
gas Returns the current call's attached amount of gas
Inline assembler is allowed through the asm
keyword
InlineAssembler = "asm" "(" Code ")" .
Code = "abcdefghijklmnopqrstuwvxyz" | "1234567890" .
int32 a = 20
int32 b = 10
if a < b {
exit()
}
this.store[a] = 10000
this.store[b] = this.origin()
for int8 i = 0; i < 10; i++ {
int32[10] out
call(0xaabbccddeeff112233445566, 0, 10000, i, out)
}
// tx without input data
transact(0xa78f6abe, 10000, nil)
// no args and return values
call(0xab, 0, 10000, nil, nil)
// create contract
big ret = create(value, 0xaabbccddeeff0099887766552211)
asm (
PUSH 10
PUSH 0
MSTORE
)