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astpretty
=========
Pretty print the output of python stdlib `ast.parse`.
astpretty is intended to be a replacement for `ast.dump`.
## Installation
`pip install astpretty`
## Usage
`astpretty` provides two api functions:
### `astpretty.pprint(node, indent=FOUR_SPACE_INDENT, show_offsets=True)`
Print a representation of the ast node.
```python
>>> astpretty.pprint(ast.parse('if x == y: y += 4').body[0])
If(
lineno=1,
col_offset=0,
test=Compare(
lineno=1,
col_offset=3,
left=Name(lineno=1, col_offset=3, id='x', ctx=Load()),
ops=[Eq()],
comparators=[Name(lineno=1, col_offset=8, id='y', ctx=Load())],
),
body=[
AugAssign(
lineno=1,
col_offset=11,
target=Name(lineno=1, col_offset=11, id='y', ctx=Store()),
op=Add(),
value=Num(lineno=1, col_offset=16, n=4),
),
],
orelse=[],
)
```
`indent` allows control over the indentation string:
```python
>>> astpretty.pprint(ast.parse('if x == y: y += 4').body[0], indent=' ')
If(
lineno=1,
col_offset=0,
test=Compare(
lineno=1,
col_offset=3,
left=Name(lineno=1, col_offset=3, id='x', ctx=Load()),
ops=[Eq()],
comparators=[Name(lineno=1, col_offset=8, id='y', ctx=Load())],
),
body=[
AugAssign(
lineno=1,
col_offset=11,
target=Name(lineno=1, col_offset=11, id='y', ctx=Store()),
op=Add(),
value=Num(lineno=1, col_offset=16, n=4),
),
],
orelse=[],
)
```
`show_offsets` controls whether the output includes line / column information:
```python
>>> astpretty.pprint(ast.parse('x += 5').body[0], show_offsets=False)
AugAssign(
target=Name(id='x', ctx=Store()),
op=Add(),
value=Num(n=5),
)
```
### `astpretty.pformat(node, indent=FOUR_SPACE_INDENT, show_offsets=True)`
Return a string representation of the ast node.
Arguments are identical to `astpretty.pprint`.
```python
>>> astpretty.pformat(ast.parse('if x == y: y += 4').body[0])
"If(\n lineno=1,\n col_offset=0,\n test=Compare(\n lineno=1,\n col_offset=3,\n left=Name(lineno=1, col_offset=3, id='x', ctx=Load()),\n ops=[Eq()],\n comparators=[Name(lineno=1, col_offset=8, id='y', ctx=Load())],\n ),\n body=[\n AugAssign(\n lineno=1,\n col_offset=11,\n target=Name(lineno=1, col_offset=11, id='y', ctx=Store()),\n op=Add(),\n value=Num(lineno=1, col_offset=16, n=4),\n ),\n ],\n orelse=[],\n)"
```
### Comparison with stdlib `ast.dump`
```python
>>> print(ast.dump(ast.parse('if x == y: y += 4').body[0]))
If(test=Compare(left=Name(id='x', ctx=Load()), ops=[Eq()], comparators=[Name(id='y', ctx=Load())]), body=[AugAssign(target=Name(id='y', ctx=Store()), op=Add(), value=Num(n=4))], orelse=[])
```
### `typed-ast` support
`astpretty` works with [typed-ast](https://github.com/python/typed_ast)!
For usage with `typed-ast` make sure you have `typed-ast` installed, a
convenient way to do this is with the `typed` extra to `astpretty`:
```bash
pip install astpretty[typed]
```
The apis above work equally well with the return values from the `ast` modules
provided by `typed_ast`:
```pycon
>>> import astpretty
>>> from typed_ast import ast3
>>> astpretty.pprint(ast3.parse('x = 4 # type: int'))
Module(
body=[
Assign(
lineno=1,
col_offset=0,
targets=[Name(lineno=1, col_offset=0, id='x', ctx=Store())],
value=Num(lineno=1, col_offset=4, n=4),
type_comment='int',
),
],
type_ignores=[],
)
```
With `typed-ast` installed, the commandline interface adds `--typed-27` and
`--typed-3` options for using the alternative ast parsers:
```console
$ astpretty --typed-3 t.py
Module(
body=[
Assign(
lineno=1,
col_offset=0,
targets=[Name(lineno=1, col_offset=0, id='x', ctx=Store())],
value=Num(lineno=1, col_offset=4, n=4),
type_comment='int',
),
],
type_ignores=[],
)
```