lewis.utils.command_builder

A fluent command builder for lewis.

Members

CmdBuilder

Build a command for the stream adapter.

class lewis.utils.command_builder.CmdBuilder(target_method, arg_sep='', ignore='', ignore_case=False)

Bases: object

Build a command for the stream adapter.

Do this by creating this object, adding the values and then building it (this uses a fluent interface).

For example to read a pressure the ioc might send “pres?” and when that happens this should call get_pres command would be: >>> CmdBuilder(“get_pres”).escape(“pres?”).build() This will generate the regex needed by Lewis. The escape is just making sure none of the characters are special reg ex characters. If you wanted to set a pressure the ioc might send “pres <pressure>” where <pressure> is a floating point number, the interface should call set_pres with that number. Now use: >>> CmdBuilder(“set_pres”).escape(“pres “).float().build() this add float as a regularly expression capture group for your argument. It is equivalent to: >>> Cmd(“set_pres”, “pres ([+-]?d+.?d*)”) There are various arguments like int and digit. Finally some special characters are included so if your protocol uses enquirey character ascii 5 you can match is using >>> CmdBuilder(“set_pres”).escape(“pres?”).enq().build()

Create a builder. Use build to create the final object

Parameters:

• target_method – name of the method target to call when the reg ex matches

• arg_sep – separators between arguments which are next to each other

• ignore – set of characters to ignore between text and arguments

• ignore_case – ignore the case when matching command

ack() → CmdBuilder

Add the ACK character (0x6) to the string.

Returns:

builder

add_ascii_character(char_number: int) → CmdBuilder

Add a single character based on its integer value, e.g. 49 is ‘a’.

Parameters:

char_number – character number

Returns:

self

any() → CmdBuilder

Add an argument that matches anything.

Returns:

builder

any_except(char: str) → CmdBuilder

Adds an argument that matches anything other than a specified character (useful for commands containing delimiters)

Parameters:

char – the character not to match

Returns:

builder

arg(arg_regex, argument_mapping: ~functools.partial = functools.partial(<class 'str'>, encoding='utf-8')) → CmdBuilder

Add an argument to the command.

Parameters:

• arg_regex – regex for the argument (capture group will be added)

• argument_mapping – the type mapping for the argument (default is str)

Returns:

builder

build(*args, **kwargs) → Cmd

Builds the CMd object based on the target and regular expression.

Parameters:

• args – arguments to pass to Cmd constructor

• kwargs – key word arguments to pass to Cmd constructor

Returns:

Cmd object

char(not_chars: None | list[str] | str = None, ignore=False) → CmdBuilder

Add a single character argument.

Parameters:

• not_chars – characters that the character can not be; None for can be anything

• ignore – True to match with a char but ignore the returned value (default: False)

Returns:

builder

digit(mapping: type = <class 'int'>, ignore: bool = False) → CmdBuilder

Add a single digit argument.

Parameters:

• mapping – The type to cast the response to (default: int)

• ignore – True to match with a digit but ignore the returned value (default: False)

Returns:

builder

enq() → CmdBuilder

Add the ENQ character (0x5) to the string.

Returns:

builder

enum(*allowed_values: AnyStr) → CmdBuilder

Matches one of a set of specified strings.

Parameters:

allowed_values – the values this function is allowed to match

Returns:

builder

eos() → CmdBuilder

Adds the regex end-of-string character to a command.

Returns:

builder

eot() → CmdBuilder

Add the EOT character (0x4) to the string.

Returns:

builder

escape(text) → CmdBuilder

Add some text to the regex which is escaped.

Parameters:

text – text to add

Returns:

builder

etx() → CmdBuilder

Add the ETX character (0x3) to the string.

Returns:

builder

float(mapping: type = <class 'float'>, ignore: bool = False) → CmdBuilder

Add a float argument.

Parameters:

• mapping – The type to cast the response to (default: float)

• ignore – True to match with a float but ignore the returned value (default: False)

Returns:

builder

get_multicommands(command_separator: AnyStr) → CmdBuilder

Allows emulator to split multiple commands separated by a defined command separator, e.g. “;”. Must be accompanied by stream device methods. See Keithley 2700 for examples

Parameters:

command_separator – Character(s) that separate commands

Returns:

builder

int(mapping: type = <class 'int'>, ignore: bool = False) → CmdBuilder

Add an integer argument.

Parameters:

• mapping – The type to cast the response to (default: int)

• ignore – True to match with a int but ignore the returned value (default: False)

Returns:

builder

optional(text) → CmdBuilder

Add some escaped text which does not necessarily need to be there. For commands with optional parameters :param text: Text to add :return: builder

regex(new_regex: str) → CmdBuilder

Add a regex to match but not as an argument.

Parameters:

new_regex – regex to add

Returns:

builder

spaces(at_least_one: bool = False) → CmdBuilder

Add a regex for any number of spaces

Parameters:

at_least_one – true there must be at least one space; false there can be any number including zero

Returns:

builder

string(length: None | int = None) → CmdBuilder

Add an argument which is a string of a given length (if blank string is any length)

Parameters:

length – length of string; None for any length

Returns:

builder

stx() → CmdBuilder

Add the STX character (0x2) to the string.

Returns:

builder