feat: add IfExpr class

[apkrelling]

Pull Request description

This PR adds IfExpr and modifies If -> IfStmt.
This PR is an attempt to resolve #93 .

• added new ASTKind
• created IfExpr class
• updated __init__.py to include the new imports and classes in the __all__ list
• added test for IfExpr
• added transpiler visit method for IfExpr
• added transpiler test for IfExpr
• added transpiler visit method for IfStmt
• added transpiler tests for IfStmt

How to test these changes

from astx.operators import BinaryOp
from astx.blocks import Block
from astx.datatypes import LiteralInt32
from astx.flows import IfExpr
from astx.transpilers import python as astx2py

# determine condition
cond = BinaryOp(op_code=">", lhs=LiteralInt32(1), rhs=LiteralInt32(2))

# create then and else blocks
then_block = Block()
else_block = Block()

# define literals
lit_2 = LiteralInt32(2)
lit_3 = LiteralInt32(3)

# define operations
op1 = lit_2 + lit_3
op2 = lit_2 - lit_3

# Add statements to the then and else blocks
then_block.append(op1)
else_block.append(op2)

# define if Expr
if_expr = IfExpr(condition=cond, then=then_block, else_=else_block)

if_expr
if_expr.__str__()

# Initialize the generator
generator = astx2py.ASTxPythonTranspiler()

# Generate Python code
generated_code = generator.visit(if_expr)
generated_code

Output of if_expr.__str__(): 'IfExpr[BinaryOp[>](LiteralInt32(1),LiteralInt32(2))]'

Output of generated_code: 'result = (2 + 3) if (1 > 2) else (2 - 3)'

Pull Request checklists

This PR is a:

• bug-fix
• new feature
• maintenance

About this PR:

• it includes tests.
• the tests are executed on CI.
• the tests generate log file(s) (path).
• pre-commit hooks were executed locally.
• this PR requires a project documentation update.

Author's checklist:

• I have reviewed the changes and it contains no misspelling.
• The code is well commented, especially in the parts that contain more
  complexity.
• New and old tests passed locally.

Additional information

Reviewer's checklist

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## Reviewer's Checklist

- [ ] I managed to reproduce the problem locally from the `main` branch
- [ ] I managed to test the new changes locally
- [ ] I confirm that the issues mentioned were fixed/resolved .

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[xmnlab]

hi @apkrelling,

about the output from the transpiler for the if expression, python has already this syntax, although it is for an inline expression.

maybe you can use this as a reference:

>>> import ast
>>> ast_text = "a = 1 if mycond == 1 else 2 if mycond == 2 else 3"
>>> pprint(ast.dump(ast.parse(ast_text)))
("Module(body=[Assign(targets=[Name(id='a', ctx=Store())], "
 "value=IfExp(test=Compare(left=Name(id='mycond', ctx=Load()), ops=[Eq()], "
 'comparators=[Constant(value=1)]), body=Constant(value=1), '
 "orelse=IfExp(test=Compare(left=Name(id='mycond', ctx=Load()), ops=[Eq()], "
 'comparators=[Constant(value=2)]), body=Constant(value=2), '
 'orelse=Constant(value=3))))], type_ignores=[])')
>>> 

[xmnlab]

for if stmt, the result from the transpiler would look like this:

if  (1 > 2):
    x = (2 + 3)
else:
    x = (2 - 3)'

[apkrelling]

Transpiler outputs:

from astx.operators import BinaryOp
from astx.blocks import Block
from astx.datatypes import LiteralInt32
from astx.flows import IfExpr, IfStmt
from astx.transpilers import python as astx2py

# determine condition
cond = BinaryOp(op_code=">", lhs=LiteralInt32(1), rhs=LiteralInt32(2))

# create then and else blocks
then_block = Block()
else_block = Block()

# define literals
lit_2 = LiteralInt32(2)
lit_3 = LiteralInt32(3)

# define operations
op1 = lit_2 + lit_3
op2 = lit_2 - lit_3

# Add statements to the then and else blocks
then_block.append(op1)
else_block.append(op2)

# define if Stmt/Expr
if_stmt1 = IfStmt(condition=cond, then=then_block, else_=else_block)
if_stmt2 = IfStmt(condition=cond, then=then_block)
if_expr1 = IfExpr(condition=cond, then=then_block, else_=else_block)
if_expr2 = IfExpr(condition=cond, then=then_block)

# Initialize the generator
generator = astx2py.ASTxPythonTranspiler()

# Generate Python code
generated_code_stmt1 = generator.visit(if_stmt1)
generated_code_stmt2 = generator.visit(if_stmt2)
generated_code_expr1 = generator.visit(if_expr1)
generated_code_expr2 = generator.visit(if_expr2)

print(generated_code_stmt1)
print(generated_code_stmt2)
print(generated_code_expr1)
print(generated_code_expr2)

Output of print(generated_code_stmt1):

if (1 > 2):
    (2 + 3)
else:
    (2 - 3)

Output of print(generated_code_stmt2):

if (1 > 2):
    (2 + 3)

Output of print(generated_code_expr1):

    (2 + 3) if  (1 > 2) else     (2 - 3)

Output of print(generated_code_expr2):

    (2 + 3) if  (1 > 2)

[apkrelling]

I updated the transpiler method for IfExpr, and now the outputs are:

Output of print(generated_code_expr1):

    (2 + 3) if  (1 > 2) else     (2 - 3)

Output of print(generated_code_expr2):

    (2 + 3) if  (1 > 2) else None

[xmnlab]

LGMT, thanks, @apkrelling !

[github-actions]

🎉 This PR is included in version 0.16.0 🎉

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