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Readme : Updated usage.
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Readme.md
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Readme.md
@ -36,6 +36,7 @@ A metaprogram is built to generate files before the main program is built. We'll
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In order to keep the locality of this code within the same files the following pattern may be used:
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In order to keep the locality of this code within the same files the following pattern may be used:
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Within `program.cpp` :
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Within `program.cpp` :
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```cpp
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```cpp
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#include "gen.hpp"
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#include "gen.hpp"
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@ -45,7 +46,7 @@ Within `program.cpp` :
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u32 gen_main()
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u32 gen_main()
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{
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{
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...
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...
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}
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}
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#endif
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#endif
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@ -53,30 +54,90 @@ u32 gen_main()
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#ifndef gen_time
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#ifndef gen_time
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#include "program.gen.cpp"
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#include "program.gen.cpp"
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// Regular runtime dependent on the generated code here.
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// Regular runtime dependent on the generated code here.
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#endif
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#endif
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```
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```
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This is ofc entirely optional and the metaprogram can be quite separated from the runtime in file organization.
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The design a constructive builder of a sort of AST for the code to generate.
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The design a constructive builder of a sort of AST for the code to generate.
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The user is given `Code` typed objects that are used to build up the AST.
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The user is given `Code` typed objects that are used to build up the AST.
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Example:
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Example using each construction interface:
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#### Upfrontl
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```cpp
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```cpp
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Code t_uw = def_type( name(uw) );
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Code t_allocator = def_type( name(allocator) );
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Code t_string_cosnt = def_type( name(char), def_specifiers( 3, ESpecifier::Const, ESpeciifer::Ptr ) );
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Code header;
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{
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Code num = def_variable( t_uw, name(Num) );
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Code cap = def_variable( t_uw, name(Capacity) );
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Code mem_alloc = def_variable( t_allocator, name(Allocator) );
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Code body = make_struct_body( num, cap, mem_alloc );
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header = def_struct( name(ArrayHeader), __, __, body );
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}
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```
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#### Incremental
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```cpp
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// Types are done the same with upfront. Incremental does not have a full interface replacment.
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// Get a Code AST from the CodePool.
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// Get a Code AST from the CodePool.
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Code header = make_struct( "Header" );
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Code header = make_struct( name(ArrayHeader) );
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{
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{
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// Make a struct body.
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// Make a struct body.
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Code body = header.body();
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Code body = header.body();
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// Members
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// Members
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body->add( def_varaible( uw, "Num") );
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body->add( def_variable( t_uw, name(Num)) );
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body->add( def_varaible( uw, "Capacity") );
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body->add( def_variable( t_uw, name(Capacity)) );
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body->add( def_varaible( allocator, "Allocator") );
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body->add( def_variable( t_allocator, name(Allocator)) );
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}
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}
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```
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```
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This will generate the following C code:
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#### Parse
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```cpp
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Code header = parse_struct( code(
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struct ArrayHeader
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{
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uw Num;
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uw Capacity;
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allocator Allocator;
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};
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));
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```
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Parse will automatically generate any types that have not been used previously.
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#### Undtyped
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```cpp
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Code header = untyped_str(
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R("struct ArrayHeader
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{
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#define Using_ArrayHeader_Data \
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uw Num; \
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uw Capacity; \
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allocator Allocator;
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Using_ArrayHeader_Data
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};)"
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);
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```
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`name` is a helper macro for providing a string literal with its size, intended for the name paraemter of functions.
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`code` is a helper macro for providing a string literal with its size, but intended for a code string parameters.
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All three constrcuton interfaces will generate the following C code:
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```cpp
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```cpp
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struct ArrayHeader
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struct ArrayHeader
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{
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{
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@ -85,6 +146,7 @@ struct ArrayHeader
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allocator Allocator;
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allocator Allocator;
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};
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};
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```
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```
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**Note: The formatting shown here is not how it will look. For your desired formatting its recommended to run a pass through the files with an auto-formatter.**
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**Note: The formatting shown here is not how it will look. For your desired formatting its recommended to run a pass through the files with an auto-formatter.**
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## Gen's DSL
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## Gen's DSL
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@ -98,22 +160,35 @@ GEN_DEFINE_DSL
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Using the previous example to show usage:
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Using the previous example to show usage:
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```cpp
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```cpp
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Code type_ns(uw) = type( uw );
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Code type_ns(allocator) = type( allocator );
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Code type_ns(string_const) = type( char, specifiers( Const, Ptr ) );
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make( struct, ArrayHeader )
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make( struct, ArrayHeader )
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{
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{
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Code
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Code
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body = ArrayHeader.body();
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body = ArrayHeader.body();
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body->add_var( uw, Num );
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body->add( variable( uw, Num ));
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body->add_var( uw, Capacity );
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body->add( variable( uw, Capacity ));
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body->add_var( allocaotr, Allocator );
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body->add( variable( allocaotr, Allocator ));
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}
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}
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// Or using parse!
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Code type_ns(uw) = type_code( uw );
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Code type_ns(allocator) = type_code( allocator );
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Code type_ns(string_const) = type_code( char const* );
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Code header = struct_code(
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struct ArrayHeader
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{
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uw Num;
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uw Capacity;
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allocator Allocator;
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};
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);
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```
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```
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The `__` represents the `UnusedCode` value constant, of unneeded varaibles.
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`type_ns` is a helper macro for providing refering to a typename if using the c-namespace naming convention.
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The DSL purposefully has no nested macros, with the follwing exceptions:
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* `__VA_ARGS__` for parameter expnasion
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* `VA_NARGS( __VA_ARGS__ )` for determing number of paramters
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* `txt(Value_)` and `txt_with_length(Value_)` to serialize a value type identifier.
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## Building
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## Building
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@ -460,11 +535,11 @@ Thus a rule of thumb is if its a simple definition you can get away with just th
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However, if:
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However, if:
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* The code being generated becomes complex
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* Your compile time complexity becomes large.
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* You enjoy actually *seeing* the generated code instead of just the error symbols or the pdb symbols.
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* You enjoy actually *seeing* the generated code instead of just the error symbols or the pdb symbols.
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* You value your debugging expereince, and would like to debug your metaprogram, without having to step through the debug version of the compiler (if you even can)
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* You value your debugging expereince, and would like to debug your metaprogram, without having to step through the debug version of the compiler (if you even can)
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* You want to roll your own runtime reflection system
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* Want to roll your own reflection system
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* You want to maintain a series of libraries for internal use, but don't want to deal with manaual merging as often when they update.
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* Want to maintain a series of libraries for internal use, but don't want to deal with manaual merging as often when they update.
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* Want to create tailored headers for your code or for your libraries since you usually don't need the majority of the code within them.
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* Want to create tailored headers for your code or for your libraries since you usually don't need the majority of the code within them.
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Then this might help you boostrap a toolset todo so.
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Then this might help you boostrap a toolset todo so.
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