introduce SCPI_HelpQ with descriptions #135

MisterHW · 2022-02-03T13:53:56Z

Human-readability is often a welcome aspect when developing software for SCPI devices, but also valuable when testing configurations or debugging issues in a lab or test setup. Command syntax and parameter ranges are traditionally only documented in manuals or programmer's guides, but often control software allows sending raw commands and performing queries.

To both help people implementing and using systems based on scpi-parser and to help projects stand the test of time, it seems valuable for the device to be able to list its supported commands, preferably with a short description exposing expected parameter types and ranges.

This PR provides

SCPI_HelpQ() callback for a "HELP?" pattern and a
USE_COMMAND_DESCRIPTIONS option which extends _scpi_command_t by a description string.

Data returned is formatted as an array of arbitrary block data. Newline characters are absorbed into the data of each block so the output is easily readable and can be parsed and displayed in control software (e.g. to provide a list of commands or syntax help).

Usage of the new features is demonstrated in the common example code.

The first column seen in the screenshot originates from the necessary block header information.

Memory Use

Backward compatibility is provided by setting USE_COMMAND_DESCRIPTIONS 0, not using SCPI_HelpQ() and if needed, by instructing the linker to drop unused sections (--gc-sections).
Even with USE_COMMAND_DESCRIPTIONS 0, the help command can provide value by accessing the pattern strings already in place.
When setting USE_COMMAND_DESCRIPTIONS 1 , _scpi_command_t is exended by a pointer (default: nullptr) to a null-terminated description string.

resolves #129

scpi-99 6.2.3.4 and 6.2.6 suggest returning multiple blocks is valid, so SCPI_ResultArbitraryBlockHeader() needs to insert a delimiter, other changes are: accepting _GLIBCXX_HAVE_STDBOOL_H, testing for non-NULL data in writeData(), and some spelling fixes.

add SCPI_HelpQ callback , optional .description strings and provide conditional initializer macros dependent on config settings for USE_COMMAND_TAGS and USE_COMMAND_DESCRIPTIONS.

introduce search string to narrow down help output

…lt disabled * Properly integrate command descriptions into examples. Preliminary descriptions added after consulting scpi-99 standard, as well as looking at the DMM and TEST handler source. Command paramater types hinted as <param> where appropriate. Return values or ranges given at the end of each description in round brackets. * Default changed to USE_COMMAND_DESCRIPTIONS 0 to avoid unexpected impact on code side. Set to 1 to use. * scpi_command_t defintion helper macros moves to types.h

* fixes some inaccuracies in scpi-def * clean-up in utils.c * add documentation to introduced functions * correct CHAR_TO_LOWER

Allow makefile to be used directly for cross-compiling (e.g. when treated as a git submodule). This requires CC and AR to be passed for a particular toolchain, but CFLAGS must also specify CPU and FPU options -> introduce MODE variable. CFLAGS cannot be passed without need to override in the makefile, so a new variable is needed. Cortex-M7 Example (linker: library and project use of VFP registers must match): CC=arm-none-eabi-gcc AR=arm-none-eabi-ar MODE="-mcpu=cortex-m7 -mthumb -mfpu=fpv5-sp-d16 -mfloat-abi=hard" (commit can be cherry-picked)

When compiled with USE_HELP_FILTER 1, HELP? accepts an optional search string -> HELP? command description extended to reflect input and output types.

j123b567

Thank you for your effort. Can you please rebase your branch to the current master? It now contains all the necessary changes to make this work. If you need to change formatting or correct typo, please provide different PR so it is easier to merge simple changes.

Can you please provide also PR for branch gh-pages so it is properly documented? Or at least a new small section to readme.md that this extension is available, how to use it and promote it that it can be helpful.

examples/common/scpi-def.c

j123b567 · 2023-01-16T09:25:21Z

examples/common/scpi-def.c


+const scpi_command_t scpi_commands[] = {


Can you please provide alternative definition files for this functionality?

It is a generally useful but unusual extension. I would like to keep examples simple. Users can decide on their own if they would like to use help command or not and it is generally not needed. It will find its way, but I would like to keep the first impression simple.

Alternatively, somehow divide the existing source (it is just an example anyway) so one part of the commands has help and the other does not so it is clear, that it is not mandatory to use and define help and tag.

scpi-def.c and scpi-def.cpp are essentially identical. scpi-def.c could be stripped down to illustrate what a version with no help and no command tags could look like. One could additionally introduce

#define NO_CMD_DESC SCPI_CMD_DESC(NULL)

which would help being explicit about the generalized structure. With scpi-def being in common, offering definitions for all possible cases seems a bit excessive to me.

Retrospective Context:
Keep in mind that prior to this PR, the default was

#define USE_COMMAND_TAGS 1

and setting it to 0 would cause a type mismatch, as in scpi-def.c/.cpp there were extra (unconditional) , 0 in the scpi_commands[] items.

The documentation on HELP? might be the best place to elaborate on way to further strip down the definition and explain the implications. This was warrented through the existence of USE_COMMAND_TAGS, and in my opinion is underscored yet again through the introduction of USE_COMMAND_DESCRIPTIONS.

Yes, scpi-def.cpp is identical to the scpi-def.c but all C specific features are removed so it can be compiled by the C++ compiler. Because this is C library, C++ file is just an example without real usage here.

Initially, examples were more about the communication interface and the command interface was the same. In the current perspective, there could be more standalone examples promoting separate features of the library, like enabling/disabling TAGs, and more importantly, introducing HELP? command.

Maybe, there can be a new example based on e.g. test-interactive to show, how HELP? command works and how to define all strings. It can have a completely different structure and its own commands definition.

examples/common/scpi-def.cpp

libscpi/Makefile

libscpi/inc/scpi/types.h

libscpi/src/utils_private.h

libscpi/src/utils.c

j123b567 · 2023-01-16T09:43:39Z

libscpi/src/utils.c

+ * @return  Pointer to first match in s if found, otherwise `NULL`.
+ * @author  Alvaro Lopez Ortega <alvaro@alobbs.com>
+ */
+char * strncasestrn (const char *s, size_t slen, const char *find, size_t findlen)


Can you please provide unit test in test_scpi_utils.c

coveralls · 2023-01-17T11:55:54Z

Coverage: 91.844% (-0.8%) from 92.594% when pulling a44b9aa on MisterHW:scpi_helpq_enhancement into e882505 on j123b567:master.

remove / comment currently unused code. Double-indirection helper definition moved to utils.h.

MisterHW · 2023-01-17T14:52:32Z

Yeah well, C89 build fails because strncasecmp() was introduced later.

j123b567 · 2023-01-17T15:22:10Z

Unfortunately, some manufacturers stick to C89 for their compilers (e.g. Microchip was using a prehistoric compiler for PIC32. Newer version is now available but hard to adopt because of frequent and incompatible changes in their core libraries)

j123b567 · 2023-01-17T15:24:28Z

You can use use SCPIDEFINE_strncasecmp instead of strncasecmp. It is already provided by the library.

This reverts commit c394eb9.

MisterHW · 2023-11-27T00:15:46Z

I will get back to this eventually :)

MisterHW added 7 commits February 1, 2022 18:48

fix typos

8ed2623

introduce SCPI_HelpQ

bc4f1d5

add SCPI_HelpQ callback , optional .description strings and provide conditional initializer macros dependent on config settings for USE_COMMAND_TAGS and USE_COMMAND_DESCRIPTIONS.

introduce help search

315f20d

introduce search string to narrow down help output

drop C++20 keyword

159fe83

rename to USE_HELP_FILTER

d099d9a

fix expression

aa660db

MisterHW mentioned this pull request Oct 26, 2022

introducing a help command #129

Open

MisterHW added 4 commits January 6, 2023 17:12

clean-up

7d0c83d

* fixes some inaccuracies in scpi-def * clean-up in utils.c * add documentation to introduced functions * correct CHAR_TO_LOWER

provide more elaborate description depending on USE_HELP_FILTER

1e1b594

When compiled with USE_HELP_FILTER 1, HELP? accepts an optional search string -> HELP? command description extended to reflect input and output types.

j123b567 requested changes Jan 16, 2023

View reviewed changes

MisterHW added 2 commits January 16, 2023 16:33

Merge branch 'j123b567:master' into scpi_helpq_enhancement

f7c4cc4

Merge branch 'j123b567:master' into scpi_helpq_enhancement

b3668be

MisterHW added 3 commits January 17, 2023 14:36

strncasestr, strncasestrn_s, pp_xstr clean-up and formatting

36ddafe

remove / comment currently unused code. Double-indirection helper definition moved to utils.h.

fix C89 issue (FALSE, for syntax)

9c66dcd

remove strcasestr

0e7c828

MisterHW added 8 commits January 17, 2023 16:51

strncasecmp -> SCPIDEFINE_strncasecmp

5dfac2b

C style comments

5153e03

split off HELP? into help.h/.c

8aa90a7

add help.c, help.h to Makefile

31a3e44

redo delete SCPI_HelpQ

d8a5d24

Revert "propagate MODE to Makefile for cross-compiling"

63f5e88

This reverts commit c394eb9.

simply SCPI_CMD_LIST_END definition

d803ffe

add missing ,

a44b9aa

Provide feedback

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introduce SCPI_HelpQ with descriptions #135

introduce SCPI_HelpQ with descriptions #135

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MisterHW commented Nov 27, 2023

introduce SCPI_HelpQ with descriptions #135

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introduce SCPI_HelpQ with descriptions #135

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