Tapas

Texas program analyzer

Getting started

Download this repo

git clone https://github.com/resin-studio/texaslang.git

Install Conda on MacOS

brew install --cask miniconda

Install Conda environment

./install_env.sh

install_env.sh uses conda to create a local environment called env from environment.yml. It's simply the following command:

conda env create --prefix=env -f ./environment.yml

Activate Conda environment

conda activate ./env

Activating the environment sets the variables of your shell and your Python to use the environment's specifications

Download tree-sitter Python parser

git clonde https://github.com/resin-studio/tree-sitter-python

Download this repo next to this repo.

Download tree-sitter Python parser

git clonde https://github.com/resin-studio/tree-sitter-python

Download the tree-sitter-python repo next to this repo.

Download Typeshed

git clone https://github.com/python/typeshed

Download the Typeshed repo next to this repo.

Build parsers

src/build_grammars.py

run this script to create build/grammars.so

Run tests

pytest -v src/test_python_analysis_system.py

Create local distribution

python setup.py install

Install package locally

pip install <local_path_to_repo>

Transliteration

from lib import python_generic_tree_system as pgs 
from lib import python_ast_system as pas
from lib import python_abstract_token_system as pats
from base import abstract_token_system as ats

code : str = ...
gnode = pgs.parse(code)
mod = pas.parse_from_generic_tree(gnode)
mod = pas.parse(code)
abstract_tokens = pas.serialize(mod)
abstract_str = pats.dump(abstract_tokens)
code_again = pats.concretize(abstract_tokens)

Transliteration internals

Syntax data model

The syntax data model is located at src/lib/python_schema_system.

To generate an abstract syntax tree (AST) model (i.e. data type) run the script src/generate_lib.py, which writes the file src/lib/python_ast_construct_autogen.py

Analysis

from lib import python_aux_system as pals
from base import abstract_token_system as ats

package = pals.analyze_typeshed()
module_name = ...
client : pals.Client = pals.spawn_analysis(package, module_name)

from typing import Iterator
token_iter : Iterator[ats.abstract_token]

inher_aux : pals.InherAux = client.init
token = next(token_iter, None)
while token:
    inher_aux = client.next(token)
    token = next(token_iter, None)
    ...
...

Semantic checks

from pyrsistent import pset
from lib import python_aux_system as pals
...

client : pals.Client = pals.spawn_analysis(package, module_name,
    checks = pals.all_checks.remove(pals.DeclareCheck())
)

Control which semantic checks are turned on with the checks parameter in spawn_analysis

from pyrsistent import pset
from lib import python_aux_system as pals
...

client : pals.Client = pals.spawn_analysis(package, module_name,
    checks = pset() 
)

Turn off all semantics checks by passing in an empty set into the checks parameter of spawn_analysis

Analysis internals

The analysis consists of three parts: the semantic data model, the program crawl, and the recording of information

Semantic data model

The semantic data model is located at src/lib/python_aux_construct_def.

The aux in the name refers to auxiliary information (as opposed to syntactic information). The construct refers to the construction of data of this model. The def is short for 'definition' because this code represents the definition of the construction of aux data, rather than the construction itself. The aux data model includes InherAux to store data that is passed as the crawling of the program proceeds across the program from left to right; SynthAux to store data that is deduced from current and child syntactic nodes and passed back up; type to represent various approximate descriptions of expressions and other elements in the program; and various other useful representations.

To generate the data model constructors run the script src/generate_lib.py, which writes the file src/lib/python_aux_construct_autogen.py

Program crawl

The program crawl is located at src/lib/python_aux_crawl_stream_def. The crawl refers to inspecting each part of a program to gather and pass some information along, and the stream refers to the program as a stream of abstract tokens. The program crawl relies on a mixture of (open) recursion and stack machines.

After processing each abstract token, the crawler writes some information to the concurrent output queue and waits for the next abstract token on the concurrent input queue.

To generate the crawler, run the script src/generate_lib.py, which writes the file src/lib/python_aux_crawl_stream_autogen.py

Information recording

The information recording is located at src/lib/python_aux_system.py. The Server class extends the server from the autogenerated program crawler. There are a few places to record information and specify how that information is passed along.

A method that starts with traverse_ takes in the InherAux of the current node and a SynthAux for each sibling to the left of the child node under consideration, and it returns an InherAux for the child node.

A method that starts with synthesize_ takes in the InherAux of the current node and for each child node, an AST and a SynthAux associated with that child node, and it returns a SynthAux for the current node.

-default behavior of traversal in method traverse_auxes -default behavior of synthesis in method synthesize_auxes -bespoke behavior of traversal for choice nodes in method traverse_<node_lhs>_<node_rhs>_<field> -bespoke behavior of synthesis for choice nodes in method synthesize_for_<node_lhs>_<node_rhs> -bespoke behavior of traversal for single nodes in method traverse_<node>_<field> -bespoke behavior of synthesis for single nodes in method synthesize_for_<node>