Kai Chappell
510e1ba683
Comprehensive test suite for SCPI command parsing: - SCPICommand dataclass tests (creation, keyword property) - Parser tests for queries, commands, arguments - IEEE 488.2 common command tests (*IDN?, *RST, etc.) - Edge cases (whitespace, empty strings) - Instrument-specific command tests Also fixed bug where is_query was determined from command string ending rather than header ending (handles queries with arguments).
88 lines
2.6 KiB
Python
88 lines
2.6 KiB
Python
"""SCPI command parsing.
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This module provides SCPI (Standard Commands for Programmable Instruments)
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command parsing for instrument communication. It handles IEEE 488.2 common
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commands (*IDN?, *RST, etc.) and instrument-specific commands.
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"""
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from dataclasses import dataclass
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@dataclass
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class SCPICommand:
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"""Parsed SCPI command.
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Attributes:
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header: The command header (e.g., "TEMP:SETPOINT" or "*IDN").
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arguments: List of command arguments (e.g., ["85.0"]).
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is_query: True if the command ends with '?' (query command).
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"""
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header: str
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arguments: list[str]
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is_query: bool
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@property
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def keyword(self) -> str:
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"""Return the command keyword without '?'.
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For query commands like "TEMP:SETPOINT?", returns "TEMP:SETPOINT".
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For regular commands like "VOLT", returns "VOLT".
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"""
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return self.header.rstrip("?")
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class SCPIParser:
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"""Parse SCPI command strings.
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Handles both IEEE 488.2 common commands (e.g., *IDN?, *RST) and
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instrument-specific commands (e.g., VOLT 3.3, TEMP:SETPOINT?).
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Examples:
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>>> parser = SCPIParser()
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>>> cmd = parser.parse("*IDN?")
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>>> cmd.header, cmd.is_query
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('*IDN?', True)
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>>> cmd = parser.parse("VOLT 3.3")
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>>> cmd.header, cmd.arguments
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('VOLT', ['3.3'])
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"""
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def parse(self, command_string: str) -> SCPICommand:
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"""Parse a SCPI command string.
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Args:
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command_string: The raw SCPI command string to parse.
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Returns:
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SCPICommand with parsed header, arguments, and query flag.
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Examples:
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"*IDN?" -> SCPICommand("*IDN?", [], True)
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"VOLT 3.3" -> SCPICommand("VOLT", ["3.3"], False)
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"TEMP:SETPOINT?" -> SCPICommand("TEMP:SETPOINT?", [], True)
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"CONF:VOLT:DC 10,0.001" -> SCPICommand("CONF:VOLT:DC", ["10", "0.001"], False)
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"""
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command_string = command_string.strip()
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if not command_string:
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return SCPICommand(header="", arguments=[], is_query=False)
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# Split into header and arguments on first whitespace
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parts = command_string.split(None, 1)
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header = parts[0]
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arguments: list[str] = []
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if len(parts) > 1:
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# Parse comma-separated arguments
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arg_string = parts[1]
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arguments = [arg.strip() for arg in arg_string.split(",")]
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# Query is determined by whether the header ends with '?'
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is_query = header.endswith("?")
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return SCPICommand(
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header=header,
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arguments=arguments,
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is_query=is_query,
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)
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