OpenEuphoria

2. Re: New pre-processor interface added to Euphoria

• Posted by jeremy (admin) Aug 04, 2009
• 1412 views

I just created the skeleton of another pre-processor. This one is a more advanced one and will not be included as a demo but hopefully it will be of use to people. It's called esql.

Here's what it does:

-- people.sql 
CREATE TABLE people ( 
  id integer primary key autoincrement, 
  first_name varchar(50) not null, 
  last_name varchar(50) not null, 
  age integer 
); 
 
CREATE INDEX people_name ON people(first_name, last_name); 
CREATE INDEX people_last_name ON people(last_name); 
CREATE INDEX people_age ON people(age); 

include esql_core.e as esql  
include people.sql as people 
 
esql:set_db("example.db") -- uses SQLite right now 
 
-- creates table if it does not already exist 
people:ensure_exists() 
 
-- automatically creates a type for the table contents and also a few creation 
-- functions 
people jim = people:empty() 
jim[people:first_name] = "Jim" 
jim[people:last_name] = "Doe" 
jim[people:age] = 30 
 
-- Saves the record to the database as automatically sets the ID 
jim = people:save(jim) 
 
people john = people:new(BLANK_ID, "John", "Doe", 33) 
john = people:save(john) 
 
-- Automatic 
object all_people = people:find_all() 
 
-- Created based on ID being a primary key 
object john_ = people:find_by_id(john[people:ID]) 
 
-- Created due to the index people_last_name 
object all_does = people:find_by_last_name("Doe") 
object all_dos = people:find_by_last_name("Do%", esql:LIKE) 
 
-- Created due to the index people_name 
object who_knows = people:find_by_name("John", "Doe") 
 
-- Automatic deleting by the primary key 
people:delete(john[people:ID]) 

All of this functionality exists right away to the Euphoria user by simply

include people.sql as people 

I'm pretty excited about all the possibilites of the pre-processor, in case you couldn't tell. Who knows what someone will come up with next.

Jeremy

4. Re: New pre-processor interface added to Euphoria

• Posted by jeremy (admin) Aug 04, 2009
• 1464 views

Oh, I was going to show how to make your pre-processor a shared library pre-processor so you can benefit from it's speed as well...

Here is the simple pre-processor we made in another thread:

-- fname_preproc.ex  
-- Print the filename when the file is included  
  
include std/io.e  
  
sequence cmds = command_line()  
sequence input_filename = cmds[3]  
sequence output_filename = cmds[4]  
  
sequence content = read_file(input_filename)  
content = "puts(1, \"Filename: " & input_filename & "\")\n" & content  
  
write_file(output_filename, content)  
abort(0)  

To make it a pre-processor that can be used as a shared library pre-processor, thus avoiding spawning a new process each call, you can simply export a function named preprocess...

-- fname_preproc.ex  
-- Print the filename when the file is included  
  
include std/io.e  
 
export function preprocess(sequence input_filename, sequence output_filename)  
    sequence content = read_file(input_filename)  
    content = "puts(1, \"Filename: " & input_filename & "\")\n" & content  
  
    write_file(output_filename, content)  
     
    return 0 -- OK 
end function 

Now, just use euc to create a DLL of it:

C:\Euphoria> euc -dll fname_preproc.ex 

Then change your pre-processor definition from stating fname_preproc.ex to fname_preproc.dll

C:\Euphoria> eui -p e,ex:fname_preproc.dll test.ex 

That's it. Now your pre-processor is fully integrated with Euphoria and processes code at lightning speed due to two reasons

1. Euphoria no longer spawns a new process for each file that has to be pre-processed.
2. Your pre-processor has been converted into C code, then compiled into a native shared library, thus you gain a considerable performance percentage due to it being native code.

Jeremy

6. Re: New pre-processor interface added to Euphoria

• Posted by jeremy (admin) Aug 04, 2009
• 1431 views

I don't think that is possible as by the time the pre-processor is running, many files may have already been parsed and the interpreter/translator has already been called. It's the interpreter and translator that manages the pre-processor, not the other way around. However, maybe I misunderstood the intention, but it seems like you want to change the way that the interpreter/translator is called via the pre-processor?

It might be better to write a little program that provides these options, then calls the interpreter/translator binary accordingly.

Also, you do not need to put \\ at the end of each line. Just type away and put a blank line in between paragraphs.

Jeremy

8. Re: New pre-processor interface added to Euphoria

• Posted by DerekParnell (admin) Aug 04, 2009
• 1409 views

By "messed up" do you mean that the lines do not break at the same place you pressed 'Enter'?

That is the way that HTML works. The Space and NewLine character are ignored when it comes to formatting lines. Lines will extend to the edge of your viewing area and this is the way that nearly everyone wants it to work.

However, if you really must have 
fixed-length lines, enclose your 
text in triple-braces, as this 
paragraph has. 

10. Re: New pre-processor interface added to Euphoria

• Posted by bernie Aug 04, 2009
• 1403 views

However, if you really must have 
fixed-length lines, enclose your 
text in triple-braces, as this 
paragraph has. 

The problem is that the web text area that I see when I am entering text is only 68 characters wide.

When I am reading messages on the euforum web text is over 100 characters.

12. Re: New pre-processor interface added to Euphoria

• Posted by jimcbrown (admin) Aug 04, 2009
• 1466 views
• Last edited Aug 05, 2009

I think what was meant was changing

entry 

into

__entry 

which is guarranteed to be unique since 4.0 allows variables to start with an underscore but earlier versions of euphoria do not, so the older 3.0 code can't possibly have another variable with the same name that'd cause a conflict.

14. Re: New pre-processor interface added to Euphoria

• Posted by euphoric (admin) Aug 05, 2009
• 1427 views

--_def.eo4		test dot notation 

Can you post the contents of _def_post.eo4? Just curious...

16. Re: New pre-processor interface added to Euphoria

• Posted by jeremy (admin) Aug 05, 2009
• 1439 views
• Last edited Aug 06, 2009

I've update the online manual and in it is a mini-guide about using the pre-processor and creating your own pre-processor.

http://openeuphoria.org/docs/eu400_0036.html

Jeremy

18. Re: New pre-processor interface added to Euphoria

• Posted by jeremy (admin) Aug 06, 2009
• 1437 views

Bernie, ... Read up a few messages, or just read this one: http://openeuphoria.org/EUforum/index.cgi?module=forum&action=message&id=107744#107744

Jeremy

20. Re: New pre-processor interface added to Euphoria

• Posted by prickle Aug 09, 2009
• 1399 views

Hey all. Just my two cents.

Would it be possible to make a preprocessor to make including shared librarys a bit easier? The ideal would be to pass it C-style headers with associated library names or wildcards and have it produce an include file containing define_c_* calls only for the corresponding method names used in the Euphoria code. The intention would be to make using shared libraries as easy as it is with C, and transparently cross-platform if at all possible.

Cheers,

Nick