sola/scpi-parser.git

			@@ -1,54 +1,54 @@
			SCPI parser library
			===========

			[SCPI](http://en.wikipedia.org/wiki/Standard_Commands_for_Programmable_Instruments) Parser library aims to provide parsing ability of SCPI commands on instrument side. All commands are defined by its patterns eg: "STATus:QUEStionable:EVENt?".
			[SCPI](http://en.wikipedia.org/wiki/Standard_Commands_for_Programmable_Instruments) Parser library aims to provide parsing ability of SCPI commands on instrument side. All commands are defined by their patterns eg: "STATus:QUEStionable:EVENt?".

			Source codes are published with open source Simplified BSD license.
			Source code is published with open source Simplified BSD license.

			Command pattern definition
			-----------
			Command pattern is defined by well known representation from SCPI instruments. Pattern is case insensitive but uses lower and upper case letters to show short and long form of the command.
			A command pattern is defined using the well known command representation from SCPI instruments. A pattern is case insensitive but uses lower and upper case letters to show the short and long form of the command.

			Pattern "SYSTem" matches strings "SYST", "syst", "SyStEm", "system", ...

			Command pattern is devided by colon ":" to show command hierarchy
			A command pattern is divided by colon ":" to show command hierarchy

			Pattern "SYSTem:VERsion?" mathes strings "SYST:version?", "system:ver?", "SYST:VER?", ...

			SCPI standard also uses brackets "[]" to define unnecesery parts of command.
			The SCPI standard also uses brackets "[]" to define optional parts of a command.

			Pattern "SYSTem:ERRor[:NEXT]?" mathes "SYST:ERR?", "system:err?" and also "system:error:next?", ...


			Command callback
			-----------
			Command callbac is defined as function with context parameter, e.g.:
			Command callback is defined as a function with a context parameter, e.g.:

			```c
			int DMM_MeasureVoltageDcQ(scpi_context_t * context)
			```

			The "Q" at the end of the function name indicates, that this function is Query function (command with "?").
			The "Q" at the end of the function name indicates that this function is a Query function (command with "?").

			The command callback can use predefined function to parse input parameters and to write output.
			The command callback can use predefined functions to parse input parameters and to write output.

			Reading input parameter is done by functions `SCPI_ParamInt`, `SCPI_ParamDouble`, `SCPI_ParamString` adn `SCPI_ParamNumber`.
			Reading input parameters is done by using the functions `SCPI_ParamInt`, `SCPI_ParamDouble`, `SCPI_ParamString` and `SCPI_ParamNumber`.

			Writing output is done by functions `SCPI_ResultInt`, `SCPI_ResultDouble`, `SCPI_ResultString`, `SCPI_ResultText`. You can write multiple output variables. They are automaticcaly separated by coma ",".
			Writing output is done by using the functions `SCPI_ResultInt`, `SCPI_ResultDouble`, `SCPI_ResultString`, `SCPI_ResultText`. You can write multiple output variables. They are automaticcaly separated by comma ",".

			Source code organisation
			------------

			Source codes are devided into few files to provide better portability to other systems.
			Source codes are divided into a few files to provide better portability to other systems.

			- libscpi/parser.c - provides the core parser library
			- libscpi/error.c - provides basic error handling (error queue of the instrument)
			- libscpi/ieee488.c - provides basic implementation of IEEE488.2 mandatory commands
			- libscpi/minimal.c - provides basic implementation of SCPI mandatory commands
			- libscpi/utils.c - provides string handling routines and conversion routines
			- libscpi/units.c - provides handling of special numners (DEF, MIN, MAX, ...) and units
			- libscpi/fifo.c - provides basic implementation of error queue FIFO
			- libscpi/debug.c - provides debug functions
			- libscpi/src/parser.c - provides the core parser library
			- libscpi/src/error.c - provides basic error handling (error queue of the instrument)
			- libscpi/src/ieee488.c - provides basic implementation of IEEE488.2 mandatory commands
			- libscpi/src/minimal.c - provides basic implementation of SCPI mandatory commands
			- libscpi/src/utils.c - provides string handling routines and conversion routines
			- libscpi/src/units.c - provides handling of special numners (DEF, MIN, MAX, ...) and units
			- libscpi/src/fifo.c - provides basic implementation of error queue FIFO
			- libscpi/src/debug.c - provides debug functions

			- examples/test-parser - is the basic non-interactive demo of the parser
			- examples/test-interactive - is the basic interactive demo of the parser
			@@ -58,7 +58,7 @@

			Implementation to your instrument
			-------------
			First of all you need to fill structure of SCPI command definitions
			First of all you need to fill the structure of SCPI command definitions

			```c
			scpi_command_t scpi_commands[] = {
			@@ -69,26 +69,26 @@
			};
			```

			Than you need to initialize interface callbacks structure. If you don't want to provide some callbacks, just initialize it as `NULL`. write callback is mandatory and is used to output data from the library.
			Then you need to initialize the interface callbacks structure. If you don't want to provide some callbacks, just initialize it as `NULL`. The write callback is mandatory and is used to output data from the library.

			```c
			scpi_interface_t scpi_interface = {
			.write = myWrite,
			.error = NULL,
			.reset = NULL,
			.test = NULL,
			.srq = NULL,
			.reset = NULL, /* Called from SCPI_CoreRst */
			.test = NULL, /* Called from SCPI_CoreTstQ */
			.control = NULL,
			};
			```

			Important thing is command buffer. Maximum size is up to you and it should be larger than any possible largest command.
			An important library component is the command buffer. The maximum size is up to you and should be larger than the largest possible command.

			```c
			#define SCPI_INPUT_BUFFER_LENGTH 256
			static char scpi_input_buffer[SCPI_INPUT_BUFFER_LENGTH];
			```

			The last structure is scpi context used in parser library.
			The last structure is the scpi context used in the parser library.

			```c
			scpi_t scpi_context = {
			@@ -104,7 +104,7 @@
			};
			```

			All these structures should be global variables of the c file or allocated by function like malloc. It is common mistake to create these structures inside a function as local variables of this function. This will not work. If you don't know why, you should read something about [function stack.](http://stackoverflow.com/questions/4824342/returning-a-local-variable-from-function-in-c).
			All these structures should be global variables of the C file or allocated by function like malloc. It is a common mistake to create these structures inside a function as local variables of this function. This will not work. If you don't know why, you should read something about [function stack.](http://stackoverflow.com/questions/4824342/returning-a-local-variable-from-function-in-c).


			Now we are ready to initialize SCPI context. It is possible to use more SCPI contexts and share some configurations (command list, registers, units list, error callback...)
			@@ -113,16 +113,16 @@
			SCPI_Init(&scpi_context);
			```

			Test implementation of function myWrite, which outputs everything to stdout, can be
			A test implementation of function myWrite, which outputs everything to stdout, could be

			```c
			size_t myWrite(scpi_context_t * context, const char * data, size_t len) {
			size_t myWrite(scpi_t * context, const char * data, size_t len) {
			(void) context;
			return fwrite(data, 1, len, stdout);
			}
			```

			Interactive demo can beimplemented using this loop
			An interactive demo can beimplemented using this loop

			```c
			#define SMALL_BUFFER_LEN
			@@ -137,7 +137,7 @@
			Implementation of command callback
			-------------

			Command callback is defined as function with result of type `scpi_result_t` and one parameter - scpi context
			Command callback is defined as a function with return value of type `scpi_result_t` and one parameter - scpi context

			```c
			scpi_result_t DMM_MeasureVoltageDcQ(scpi_t * context)
			@@ -147,7 +147,7 @@

			You can read command parameters and write command results. There are several functions to do this.

			Every time, you call function to read parameter, it shifts pointers to the next parameter. You can't read specified parameter directly by its index - e.g.
			Every time you call a function to read a command parameter, it shifts pointers to the next parameter. You can't read specified parameter directly by its index - e.g.

			```c
			// pseudocode
			@@ -160,7 +160,7 @@

			If you discard some parameters, there is no way to recover them.

			These are the functions, you can use to read parameters
			These are the functions, you can use to read command parameters
			- `SCPI_ParamInt` - read signed 32bit integer value (dec or hex with 0x prefix)
			- `SCPI_ParamDouble` - read double value
			- `SCPI_ParamNumber` - read double value with or without units or represented by special number (DEF, MIN, MAX, ...). This function is more universal then SCPI_ParamDouble.
			@@ -169,11 +169,11 @@
			- `SCPI_ParamBool` - read boolean value (ON, OFF, 0, 1)
			- `SCPI_ParamChoice` - read enumeration value eg. (BUS, IMMediate, EXTernal) defined by parameter

			These are the functions, you can use to write results
			These are the functions, you can use to write command results
			- `SCPI_ResultInt` - write integer value
			- `SCPI_ResultDouble` - write double value
			- `SCPI_ResultText` - write text value encapsulated in ""
			- `SCPI_ResultString` - directly write string value
			- `SCPI_ResultBool` - write boolean value

			You can use function `SCPI_NumberToStr` to convert number with units to textual representation and then use `SCPI_ResultString` to write this to the user.
			You can use the function `SCPI_NumberToStr` to convert number with units to textual representation and then use `SCPI_ResultString` to write this to the user.