# Solidity to FunC


## Requirements

- [sold](https://github.com/tonlabs/TON-Solidity-Compiler/releases)
- [tonos-cli](https://github.com/tonlabs/tonos-cli/releases)
- [fift, func](https://github.com/ton-blockchain/ton/releases)

### Via Docker

alias docker-run='docker run --rm -i -v $(pwd):/src -w /src'
alias tvm-action='docker-run ghcr.io/ever-guild/tvm-action'
alias sold='tvm-action sold'
alias tonos-cli='tvm-action tonos-cli'
alias fift='tvm-action fift'
alias func='tvm-action func'

## Usage

### Step 1 `sol > tvc`

Create a file `App.sol` with the following content:

pragma ever-solidity >= 0.71.0;

contract App {
    function add(int a, int b) public pure returns (int) {
        return a + b;
    }
}

Compile `solidity` to `tvc`:

sold App.sol

### Step 2 `tvc > boc`

Extract the code of the contract:

tonos-cli -j decode stateinit --tvc App.tvc | jq -r .code | base64 -d > App.boc

### Step 3 `boc > fift`

Get function ID `int` value:

echo $((16#$(sold --function-ids App.sol | jq -r .add | cut -d'x' -f2)))

For signature `add(int, int)(int)`, the function ID is `1347459865`

Decompile `App.boc`:

echo '"Disasm.fif" include "App.boc" file>B B>boc <s disasm cr' | fift | grep -v 'ok' > App.fif

Result:

...
1347459865 PUSHINT
EQUAL
IFJMP:<{
  %COPY CODE%
}>
...

### Step 4 `fift > func`

Create a file `App.fc` with the following content:

() recv_internal() { }

(int) code(int a, int b) asm """
  DROP
  6 GETGLOB
  76 THROWIFNOT
  OVER
  IF:<{
    256 LDI
    LDREF
    ENDS
    CTOS
  }>ELSE<{
    256 LDI
  }>
  256 LDI
  ENDS
  CALL:<{
    ADD
    256 FITS
  }>
  OVER
  IF:<{
    s3 PUSH
    CTOS
    2 LDU
    LDMSGADDR
    DROP
    NIP
    NEWC
    x{C} STSLICECONST
    STSLICE
    3494943513 PUSHINT
    130 UR
    256 STI
    ENDC
    0 PUSHINT
    SENDRAWMSG
  }>ELSE<{
    DROP
  }>
  IF:<{
    3 GETGLOB
    2 GETGLOB
    NEWC
    256 STU
    64 STU
    x{C_} STSLICECONST
    ENDC
    c4 POP
  }>
  0 THROW
""";

(int) add(int a, int b) method_id {
  return code(a, b);
}

### Step 4 `func > fift > boc`

Compile `func` to `boc`:

func -SPA -o App.fif -W App.boc App.fc && fift App.fif

> 🤷🏻‍♂️ At this step, most likely you will get an error: `Error interpreting file 'App.fif': App.fif:25: CALL:<{:-?`, if this is not the case and you have successfully completed this impossible mission, please let me know in a comment, I will be glad for any of your feedback and suggestions 🖖🏻