Difference between revisions of "DIP41"
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| − | == DIP 41: dmd command line overhaul. (still editing : don't | + | == DIP 41: dmd command line overhaul. (still editing : don't read yet) == |
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== Abstract == | == Abstract == | ||
| + | This DIP seeks to improve dmd's command line flags, to make it more consistent with other tools, more expandable, and better interact with other tools such as rdmd. | ||
| + | |||
| + | == -offilename vs -of=filename == | ||
Dmd currently uses 2 conventions for its flags with arguments: | Dmd currently uses 2 conventions for its flags with arguments: | ||
| − | * | + | * type A: -offilename, -Dddocdir, -Dffilename, -Ipath (etc) |
| − | + | * type B: -version=ident (etc) | |
| − | |||
| − | |||
| − | |||
| − | |||
| − | -Dddocdir | ||
| − | -Dffilename | ||
| − | -Ipath | ||
| − | - | ||
| − | (etc | ||
| − | + | Type A, the most common in dmd, is problematic: | |
| − | + | * it doesn't scale: we can't have any new flag starting with "-I" or "-L", etc as it would create conflicts. | |
| + | * it's visually harder to tell from the command line the options from the arguments to these options | ||
| + | * it's using a different (worst) convention from most other tools (including other D compilers, like gdc or ldc) | ||
| − | -Dd=docdir | + | For reference, ldc uses: |
| − | -Df=filename | + | -of=filename, -Dd=docdir, -Df=filename, -I=path etc. |
| − | -I=path | ||
| − | |||
| − | + | == Deprecation path == | |
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| − | + | We should support type B convention for all flags in a future release of dmd, and support the existing ones for some time until they become deprecated. | |
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| − | support | ||
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1) | 1) | ||
| − | + | Make all future flags have type B. | |
2) | 2) | ||
| − | + | Migrate all A flags to B flags. Here's one possible way to achieve this (say in next dmd release): | |
| − | this (say in next dmd release): | ||
| − | dmd -offilename main.d //works but generates a warning for now, and | + | dmd -offilename main.d //works but generates a warning for now, and error in a subsequent dmd release |
| − | error | ||
dmd -old_flag -offilename main.d //works and doesn't generate a warning. | dmd -old_flag -offilename main.d //works and doesn't generate a warning. | ||
| − | dmd -new_flag -of=filename main.d //works. After a certain time | + | dmd -new_flag -of=filename main.d //works. After a certain time passed, -new_flag is implied |
| − | passed, -new_flag is implied | ||
| − | Note, A and B flags can't be mixed, eg: -offilename -Ddoc=dir will | + | Note, A and B flags can't be mixed, eg: -offilename -Ddoc=dir will give error, in all 3 cases above (ie for flags that are currently in the A style). |
| − | give error, in all 3 cases above (ie for flags that are currently in | ||
| − | the A style). | ||
| − | 2b) Alternative: use a new binary name (dmd2) instead of -newflag. I | + | 2b) Alternative: use a new binary name (dmd2, reminds of D2, ldc2, ldmd2) instead of -newflag. I don't like this as much somehow. |
| − | don't like this as much somehow. | ||
3) | 3) | ||
| − | can we deprecate the current behavior where one can pass the file name | + | can we deprecate the current behavior where one can pass the file name without extension (main vs main.d) as source? Consistency is better than avoiding to type those 2 characters. I created a pathological case with main.d is conflicting with main.d.d (with different |
| − | without extension (main vs main.d) as source? Consistency is better | ||
| − | than avoiding to type those 2 characters. I created a pathological | ||
| − | case with main.d is conflicting with main.d.d (with different | ||
contents). Which one do you think is called when we call rdmd main.d ? | contents). Which one do you think is called when we call rdmd main.d ? | ||
| − | Note, I raised a very analogous concern here | + | Note, I raised a very analogous concern here [https://github.com/D-Programming-Language/dmd/pull/1871#issuecomment-16101987] regarding naming of object files in a flat hierarchy (see my example with dmd -c -oq foo/mod.d foo_mod.d) |
| − | https://github.com/D-Programming-Language/dmd/pull/1871#issuecomment-16101987 | ||
| − | regarding naming of object files in a flat hierarchy (see my example | ||
| − | with dmd -c -oq foo/mod.d foo_mod.d) | ||
4) | 4) | ||
| − | The current strategy of rdmd is to treat as input arguments anything | + | The current strategy of rdmd is to treat as input arguments anything after the first source file: |
| − | after the first source file: | + | rdmd main.d myfirstprogramarg // a bit awkward, especially with optional extension it gets hard to parse visually. |
| − | rdmd main.d myfirstprogramarg // a bit awkward, especially with | ||
| − | optional extension it gets hard to parse visually. | ||
This is error prone, and inconsistent with dmd's behavior, which is: | This is error prone, and inconsistent with dmd's behavior, which is: | ||
| − | dmd src1.d -run main.d myfirstprogramarg //a bit awkward, need to | + | dmd src1.d -run main.d myfirstprogramarg //a bit awkward, need to split the source from the main file. |
| − | split the source from the main file. | ||
| − | I suggest instead something simpler, explicit and consistent, using | + | I suggest instead something simpler, explicit and consistent, using -args as a dmd command line argument, that would just work as well with rdmd: |
| − | -args as a dmd command line argument, that would just work as well | ||
| − | with rdmd: | ||
dmd main.d src1.d -args myfirstprogramarg | dmd main.d src1.d -args myfirstprogramarg | ||
rdmd main.d -args myfirstprogramarg | rdmd main.d -args myfirstprogramarg | ||
| − | |||
5) | 5) | ||
| − | currently we distinguish rdmd's arguments from dmd's arguments via | + | currently we distinguish rdmd's arguments from dmd's arguments via '--' vs '-'. A better way IMO would be to have a special flag indicating the start of dmd's (or gdc/ldc...) flags: eg |
| − | '--' vs '-'. A better way IMO would be to have a special flag | ||
| − | indicating the start of dmd's (or gdc/ldc...) flags: eg | ||
rdmd --chatty --dflags -version=myversion main.d | rdmd --chatty --dflags -version=myversion main.d | ||
Notes: | Notes: | ||
Has support of Walter ([http://forum.dlang.org/post/kk4ejt$1pnq$1@digitalmars.com here]) | Has support of Walter ([http://forum.dlang.org/post/kk4ejt$1pnq$1@digitalmars.com here]) | ||
Revision as of 08:08, 21 May 2013
Contents
DIP 41: dmd command line overhaul. (still editing : don't read yet)
| Title: | dmd command line overhaul. |
|---|---|
| DIP: | 41 |
| Version: | 1 |
| Status: | Draft |
| Created: | 2013-05-20 |
| Last Modified: | 2013-05-20 |
| Author: | Timothee Cour |
| Links: | dmd command line options bad design: -offilename, -Ddocdir etc. |
Abstract
This DIP seeks to improve dmd's command line flags, to make it more consistent with other tools, more expandable, and better interact with other tools such as rdmd.
-offilename vs -of=filename
Dmd currently uses 2 conventions for its flags with arguments:
- type A: -offilename, -Dddocdir, -Dffilename, -Ipath (etc)
- type B: -version=ident (etc)
Type A, the most common in dmd, is problematic:
- it doesn't scale: we can't have any new flag starting with "-I" or "-L", etc as it would create conflicts.
- it's visually harder to tell from the command line the options from the arguments to these options
- it's using a different (worst) convention from most other tools (including other D compilers, like gdc or ldc)
For reference, ldc uses: -of=filename, -Dd=docdir, -Df=filename, -I=path etc.
Deprecation path
We should support type B convention for all flags in a future release of dmd, and support the existing ones for some time until they become deprecated.
1) Make all future flags have type B.
2) Migrate all A flags to B flags. Here's one possible way to achieve this (say in next dmd release):
dmd -offilename main.d //works but generates a warning for now, and error in a subsequent dmd release dmd -old_flag -offilename main.d //works and doesn't generate a warning. dmd -new_flag -of=filename main.d //works. After a certain time passed, -new_flag is implied
Note, A and B flags can't be mixed, eg: -offilename -Ddoc=dir will give error, in all 3 cases above (ie for flags that are currently in the A style).
2b) Alternative: use a new binary name (dmd2, reminds of D2, ldc2, ldmd2) instead of -newflag. I don't like this as much somehow.
3) can we deprecate the current behavior where one can pass the file name without extension (main vs main.d) as source? Consistency is better than avoiding to type those 2 characters. I created a pathological case with main.d is conflicting with main.d.d (with different contents). Which one do you think is called when we call rdmd main.d ? Note, I raised a very analogous concern here [1] regarding naming of object files in a flat hierarchy (see my example with dmd -c -oq foo/mod.d foo_mod.d)
4) The current strategy of rdmd is to treat as input arguments anything after the first source file: rdmd main.d myfirstprogramarg // a bit awkward, especially with optional extension it gets hard to parse visually.
This is error prone, and inconsistent with dmd's behavior, which is: dmd src1.d -run main.d myfirstprogramarg //a bit awkward, need to split the source from the main file.
I suggest instead something simpler, explicit and consistent, using -args as a dmd command line argument, that would just work as well with rdmd:
dmd main.d src1.d -args myfirstprogramarg rdmd main.d -args myfirstprogramarg
5) currently we distinguish rdmd's arguments from dmd's arguments via '--' vs '-'. A better way IMO would be to have a special flag indicating the start of dmd's (or gdc/ldc...) flags: eg rdmd --chatty --dflags -version=myversion main.d
Notes: Has support of Walter (here)
