Code Generation

Tools for generating executable Python code from flowgraphs.

`generate_code`

Generate Python/C++ code from the current flowgraph.

Unlike the grcc command-line tool, this does not block on validation errors. Validation warnings are included in the response for reference.

Parameters

Name	Type	Default	Description
`output_dir`	`str`	`""`	Output directory (defaults to temp directory)

Returns

Type: GeneratedCodeModel

Generated code result with path, validity, and warnings.

Example

result = generate_code(output_dir="/tmp")
# Returns: GeneratedCodeModel(
#   file_path="/tmp/fm_receiver.py",
#   is_valid=True,
#   warnings=[]
# )

# With validation warnings
result = generate_code()
# Returns: GeneratedCodeModel(
#   file_path="/tmp/tmpXXXXXX/fm_receiver.py",
#   is_valid=False,
#   warnings=["audio_sink_0: Sample rate mismatch"]
# )

Notes

Generated code includes XML-RPC server if the flowgraph has XML-RPC variables
Output type (Python/C++) depends on generate_options in flowgraph options
File name is derived from flowgraph title

`evaluate_expression`

Evaluate a Python expression in the flowgraph’s namespace.

Useful for testing parameter expressions before setting them.

Parameters

Name	Type	Default	Description
`expr`	`str`	-	Python expression to evaluate

Returns

Type: Any

Result of the expression evaluation.

Example

# Arithmetic
result = evaluate_expression("101.1e6 + 200e3")
# Using numpy (available in flowgraph namespace)
result = evaluate_expression("np.pi * 2")
# Returns: 6.283185307179586

# Complex expressions
result = evaluate_expression("int(2e6 / 10)")
# Returns: 200000

`create_embedded_python_block`

Create an embedded Python block from source code.

Parameters

Name	Type	Default	Description
`source_code`	`str`	-	Python source code for the block
`block_name`	`str \| None`	`None`	Optional custom block name

Returns

Type: str

The assigned block name.

Example

source = '''
import numpy as np
from gnuradio import gr

class my_multiplier(gr.sync_block):
    """Multiply input by a constant."""

    def __init__(self, multiplier=2.0):
        gr.sync_block.__init__(
            self,
            name="my_multiplier",
            in_sig=[np.complex64],
            out_sig=[np.complex64]
        )
        self.multiplier = multiplier

    def work(self, input_items, output_items):
        output_items[0][:] = input_items[0] * self.multiplier
        return len(output_items[0])
'''

name = create_embedded_python_block(source_code=source)
# Returns: "epy_block_0"

# With custom name
name = create_embedded_python_block(
    source_code=source,
    block_name="multiplier"
)
# Returns: "multiplier_0"

Notes

Embedded blocks must inherit from gr.sync_block, gr.decim_block, or gr.interp_block
The block class must define __init__ and work methods
Use set_block_params() to configure the block after creation