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https://github.com/federicobruzzone/smaller-basic
A Python interpreter using ANTLR4 as a parser generator for a version of Microsoft's Small Basic language renamed "Smaller Basic."
https://github.com/federicobruzzone/smaller-basic
basic compiler interpreter language python smallbasic smallbasic-lang
Last synced: 2 months ago
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A Python interpreter using ANTLR4 as a parser generator for a version of Microsoft's Small Basic language renamed "Smaller Basic."
- Host: GitHub
- URL: https://github.com/federicobruzzone/smaller-basic
- Owner: FedericoBruzzone
- License: gpl-3.0
- Created: 2023-06-23T07:34:08.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2024-08-12T16:08:48.000Z (5 months ago)
- Last Synced: 2024-08-12T18:30:17.799Z (5 months ago)
- Topics: basic, compiler, interpreter, language, python, smallbasic, smallbasic-lang
- Language: Python
- Homepage:
- Size: 6.37 MB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Smaller Basic
A Python interpreter using ANTLR4 as a parser generator for a version of Microsoft's Small Basic language renamed "Smaller Basic."
## Examples of source code
Location of this source code: `source_code/source.sb`.
```python
Sub x_as_int
If (x = "1") Then x = 1 EndIf
If (x = "2") Then x = 2 EndIf
If (x = "3") Then x = 3 EndIf
If (x = "4") Then x = 4 EndIf
If (x = "5") Then x = 5 EndIf
If (x = "6") Then x = 6 EndIf
If (x = "7") Then x = 7 EndIf
If (x = "8") Then x = 8 EndIf
If (x = "9") Then x = 9 EndIf
EndSub
Sub main
While (true)
IO.WriteLine("Enter a number from 0 to 9: ")
x = IO.ReadLine()
x_as_int()
IO.WriteLine("Enter your name: ")
name = IO.ReadLine()
For i = 0 To x Step 2
IO.WriteLine("Hello " + name)
EndFor
EndWhile
EndSub
main()
```
AST
The output of this source code is:
```bash
+---------------------------------------+
| ----- Run source_code/source.sb ----- |
+---------------------------------------+
Enter a number from 0 to 9:
|> 8
Enter your name:
|> Federico
Hello Federico
Hello Federico
Hello Federico
Hello Federico
```
Example using Library, Array and Goto statements [source_code/first_prog.sb]
```python
Sub init_value_as_int
If (init_value = "1") Then init_value = 1 EndIf
If (init_value = "2") Then init_value = 2 EndIf
If (init_value = "3") Then init_value = 3 EndIf
If (init_value = "4") Then init_value = 4 EndIf
If (init_value = "5") Then init_value = 5 EndIf
If (init_value = "6") Then init_value = 6 EndIf
If (init_value = "7") Then init_value = 7 EndIf
If (init_value = "8") Then init_value = 8 EndIf
If (init_value = "9") Then init_value = 9 EndIf
EndSub
Sub ArrayInit
For i = 0 To 3
For j = 0 To 3
my_vec[i][j] = init_value
EndFor
EndFor
EndSub
Sub ArrayIncrement
For i = 0 To 3
For j = 0 To 3
my_vec[i][j] = my_vec[i][j] + 1
EndFor
EndFor
EndSub
Sub Main
my_vec[2][2] = 0
IO.WriteLine(my_vec)
count = 0
LabelFor5:
IO.WriteLine(count)
IO.WriteLine("Enter the value with which you want to initialize the array: ")
init_value = IO.ReadLine()
If (String.Length(init_value) > 1) Then
IO.WriteLine("You entered more than one character. Only the first character will be used.")
init_value = String.Substr(init_value, 0, 1)
EndIf
init_value_as_int()
ArrayInit()
IO.WriteLine(my_vec)
ArrayIncrement()
IO.WriteLine(my_vec)
count = count + 1
If (count < 5) Then
Goto LabelFor5
EndIf
Goto End
While (my_vec[2][2] < 10)
ArrayIncrement()
IO.WriteLine(my_vec)
EndWhile
EndSub
Main()
End:
IO.WriteLine("End of program.")
```
Example using nested Goto [source_code/second_prog.sb]
```python
a = 1
Loop1:
IO.WriteLine("Loop1")
Loop2:
IO.WriteLine("Loop2")
a = a + 1
If (a < 10) Then
Goto Loop2
EndIf
IO.WriteLine(a)
a = a + Math.Sqrt(a)
IO.WriteLine(a)
If (a > 100) Then
Goto End
EndIf
Goto Loop1
End:
IO.WriteLine("End")
```
Parsing errors and warnings are displayed as follows:
## Project directory structure
```
.
├── source_code
│ ├── ...
└── src
├── abstract_syntax_tree
│ ├── ...
├── error
│ ├── ...
├── grammar
│ ├── SmallerBasic.g4
│ └── ...
├── interpreter
│ ├── dispatch_table.py
│ ├── global_memory.py
│ ├── interpreter.py
│ └── library
│ └── ...
├── main.py
└── utils
└── ...
```
### Overview
- `source_code`: This directory contains the source code files of SmallerBasic programming language.
- `src`: The main source code directory containing various subdirectories and files related to the interpreter and language implementation.
- `abstract_syntax_tree`: This directory hold files related to constructing and manipulating the abstract syntax tree.
- `error`: This directory there are files related to error handling and reporting within the interpreter.
- `grammar`: This directory contain the grammar definition files, such as `SmallerBasic.g4`, which define the syntax and structure of the SmallerBasic language using ANTLR grammar notation.
- `interpreter`: This is a crucial directory containing the implementation of the interpreter for the SmallerBasic language.
- `dispatch_table.py`: This file contains the implementation of a dispatch table used for efficiently executing different language constructs.
- `global_memory.py`: This file contains the code related to managing the global memory and variables within the interpreter.
- `interpreter.py`: This is the main interpreter implementation that executes SmallerBasic programs by traversing the abstract syntax tree and performing actions based on the language constructs.
- `library`: This directory contain the library files that provide built-in functions or utilities for SmallerBasic programs, for example `IO`, `Math` and `String` libraries.
- `main.py`: This is the entry point of your interpreter, where execution starts when running the interpreter.
- `utils`: This directory could hold utility files that are used throughout the project, for example the metaclass that colors prints.
## Starting point working locally
**Create and start a new virtual environment**
`source create_venv.sh venv`
**Start current virtual environment**
`source venv/bin/activate`
**Deactivate the current virtual environment**
`deactivate`
## Usage
```
Usage: smallbasic [OPTION] [FILE]
Run Smaller Basic program
Options:
-h display this help and exit
-g generate grammar
-gas generate grammar and run all files in source_code folder
-as run all files in source_code folder
```
## Interpreter
### Run a file
`smallbasic .sb`
For example, you can ri-generate the grammar and run a file in `source_code` directory in the following way:
`smallbasic -g source_code/source.sb`
### Generate grammar
`antlr4 -Dlanguage=Python3 -visitor src/grammar/SmallerBasic.g4`
- **Requirements**: the same or greater java version used to compile the antlr4 jar. (in our case **java-18-openjdk-amd64**)
- Change version of java: `update-alternatives --config java`.
- `antlr4` is an alias generated by the `create_venv.sh` file.
### Run a file using `python3` interpreter
`python3 -m src.main source_code/.sb`
## Contributing
Contributions to this project are welcome! If you have any suggestions, improvements, or bug fixes, feel free to submit a pull request.
## License
This repository is licensed under the [GNU General Public License (GPL)](https://www.gnu.org/licenses/gpl-3.0.html). Please review the license file provided in the repository for more information regarding the terms and conditions of the GPL license.
## Contact
If you have any questions, suggestions, or feedback, do not hesitate to [contact me](https://federicobruzzone.github.io/).