Neptune

Python compiler for Ontology

• Free software: LGPL license
  • Overview
  • Installation
  • Usage
  • License
  • DebugInfo

Overview

Neptune is a tool for compiling Python files to the .avm format for usage in smart contracts on the Ontology blockchain. It currently only supports a subset of the Python language.

What does it currently do

• Compiles a subset of the Python language to the .avm format for use in the Ontology blockchain
• Works for Python 3.6+

What will it do

• Compile a larger subset of the Python language
• Additional syntax checks
• Optimize instr stream

What's new compared to neo-boa

• Basic abstract syntax trees
• Ability to write numerous expressions per line. (See Example)
• global keyword, works the same as global in the standard python library. Allows functions to share variables. (See Example #1) (See Example #2)
• Cascade bool operation. (See Example)
• Augmented assignment operators such as += *= /= -= (See Example)
• Chained comparisons (See Example)
• Chained assignment
• Maps nested within maps. (See Example)
• if expression statements. (See Example)
• for, while, break and continue. (See Example #1) (See Example #2)
• if x in y statements. (See Example)
• loop else statements. (See Example)
• range(len), range(start, stop), range(start, stop, step). (See Example)
• Function default argument (See Example)
• Function variable argument (See Example)
• Pass Starred argument for function call (See Example)
• List comprehension. (See Example)
• Dict comprehension. (See Example)
• Conditional operation
• Assert. (See Example)
• String slicing (See Example)
• Added libont.py to support various list functions such as list removal and element in
• Additional syntax checks
• More accurate debug messages

Installation

Installation requires Python version 3.6 or later.

Setup

Clone the repository and navigate into the project directory. Make a Python 3 virtual environment and activate it via:

python3 -m venv venv
source venv/bin/activate

Then, install the requirements:

pip install -r requirements.txt

Usage

Import the compiler into a file with:

from ontology.compiler import Compiler

The compiler can be used in three different ways:

1. Compiling a python file to a new file

# Compiles the python file and creates an avm in 'path/to/your/file.avm'.
compiler = Compiler.Compile('path/to/your/file.py')

1. Compiling a python file to .avm

# Compiles the python file and returns an avm.
avm = Compiler.Compile_File('path/to/your/file.py')

1. Compiling a variable to .avm

# Compiles a contract stored in memory and returns an avm.
avm = Compiler.Compile_Contract('def Main(operation, args): ...')

You can also print out the instr instream:

compiler.DumpAsm()

Testing

You can run the tests using the runall.bash or runall-testing.bash files located in ontology_test. You can run the compiler tests using the compile-avm-test.py file in the root directory.

Contributing

Contributors are welcome to the ontology-python-compiler. Before beginning, please take a look at our contributing guidelines. You can open an issue by clicking here.

If you have any issues getting setup, open an issue or reach out in the Ontology Discord.

License

• Open-source LGPL.
• Main author is @steven

DebugInfo

FuncName: indicate the opcode blongs to which function. Global#Code is for Code in Global.

Lineno: indicate the opcode blongs to which line number in source code.

Col : indicate the opcode blongs to which columns in source code.

offset: the address of Opcode. from 0 to len of avm.

Opcode: the Opcode.

JumpTarget: the target address(offset) of jump instruct.

TargetOff: the relative offset between target address and current jump instruction.

FuncName                       Lineno     Col   Offset     OpCode               JumpTarget           TargetOff           
Global#Code                    1          0     0          PUSH2               
Global#Code                    1          0     1          NEWARRAY            
Global#Code                    1          0     2          TOALTSTACK          
Global#Code                    1          14    3          PUSHBYTES5          
Global#Code                    1          0     9          DUPFROMALTSTACK     
Global#Code                    1          0     10         PUSH0               
Global#Code                    1          0     11         PUSH2               
Global#Code                    1          0     12         ROLL                
Global#Code                    1          0     13         SETITEM             
Global#Code                    3          4     14         PUSH2               
Global#Code                    3          0     15         DUPFROMALTSTACK     
Global#Code                    3          0     16         PUSH1               
Global#Code                    3          0     17         PUSH2               
Global#Code                    3          0     18         ROLL                
Global#Code                    3          0     19         SETITEM             
Global#Code                    4          0     20         FROMALTSTACK        
Main                           4          0     21         PUSH3               
Main                           4          0     22         NEWARRAY            
Main                           4          0     23         TOALTSTACK          
Main                           4          0     24         DUPFROMALTSTACK     
Main                           4          0     25         PUSH0               
Main                           4          0     26         PUSH2               
Main                           4          0     27         ROLL                
Main                           4          0     28         SETITEM             
Main                           5          8     29         PUSH0               
Main                           5          4     30         DUPFROMALTSTACK     
Main                           5          4     31         PUSH1               
Main                           5          4     32         PUSH2               
Main                           5          4     33         ROLL                
Main                           5          4     34         SETITEM             
Main                           6          8     35         DUPFROMALTSTACK     
Main                           6          8     36         PUSH0               
Main                           6          8     37         PICKITEM            
Main                           6          8     38         CALL                 49                   11