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diff --git a/googletest/docs/V1_7_PumpManual.md b/googletest/docs/V1_7_PumpManual.md deleted file mode 100644 index 8184f15..0000000 --- a/googletest/docs/V1_7_PumpManual.md +++ /dev/null @@ -1,177 +0,0 @@ - - -<b>P</b>ump is <b>U</b>seful for <b>M</b>eta <b>P</b>rogramming. - -# The Problem # - -Template and macro libraries often need to define many classes, -functions, or macros that vary only (or almost only) in the number of -arguments they take. It's a lot of repetitive, mechanical, and -error-prone work. - -Variadic templates and variadic macros can alleviate the problem. -However, while both are being considered by the C++ committee, neither -is in the standard yet or widely supported by compilers. Thus they -are often not a good choice, especially when your code needs to be -portable. And their capabilities are still limited. - -As a result, authors of such libraries often have to write scripts to -generate their implementation. However, our experience is that it's -tedious to write such scripts, which tend to reflect the structure of -the generated code poorly and are often hard to read and edit. For -example, a small change needed in the generated code may require some -non-intuitive, non-trivial changes in the script. This is especially -painful when experimenting with the code. - -# Our Solution # - -Pump (for Pump is Useful for Meta Programming, Pretty Useful for Meta -Programming, or Practical Utility for Meta Programming, whichever you -prefer) is a simple meta-programming tool for C++. The idea is that a -programmer writes a `foo.pump` file which contains C++ code plus meta -code that manipulates the C++ code. The meta code can handle -iterations over a range, nested iterations, local meta variable -definitions, simple arithmetic, and conditional expressions. You can -view it as a small Domain-Specific Language. The meta language is -designed to be non-intrusive (s.t. it won't confuse Emacs' C++ mode, -for example) and concise, making Pump code intuitive and easy to -maintain. - -## Highlights ## - - * The implementation is in a single Python script and thus ultra portable: no build or installation is needed and it works cross platforms. - * Pump tries to be smart with respect to [Google's style guide](http://code.google.com/p/google-styleguide/): it breaks long lines (easy to have when they are generated) at acceptable places to fit within 80 columns and indent the continuation lines correctly. - * The format is human-readable and more concise than XML. - * The format works relatively well with Emacs' C++ mode. - -## Examples ## - -The following Pump code (where meta keywords start with `$`, `[[` and `]]` are meta brackets, and `$$` starts a meta comment that ends with the line): - -``` -$var n = 3 $$ Defines a meta variable n. -$range i 0..n $$ Declares the range of meta iterator i (inclusive). -$for i [[ - $$ Meta loop. -// Foo$i does blah for $i-ary predicates. -$range j 1..i -template <size_t N $for j [[, typename A$j]]> -class Foo$i { -$if i == 0 [[ - blah a; -]] $elif i <= 2 [[ - blah b; -]] $else [[ - blah c; -]] -}; - -]] -``` - -will be translated by the Pump compiler to: - -``` -// Foo0 does blah for 0-ary predicates. -template <size_t N> -class Foo0 { - blah a; -}; - -// Foo1 does blah for 1-ary predicates. -template <size_t N, typename A1> -class Foo1 { - blah b; -}; - -// Foo2 does blah for 2-ary predicates. -template <size_t N, typename A1, typename A2> -class Foo2 { - blah b; -}; - -// Foo3 does blah for 3-ary predicates. -template <size_t N, typename A1, typename A2, typename A3> -class Foo3 { - blah c; -}; -``` - -In another example, - -``` -$range i 1..n -Func($for i + [[a$i]]); -$$ The text between i and [[ is the separator between iterations. -``` - -will generate one of the following lines (without the comments), depending on the value of `n`: - -``` -Func(); // If n is 0. -Func(a1); // If n is 1. -Func(a1 + a2); // If n is 2. -Func(a1 + a2 + a3); // If n is 3. -// And so on... -``` - -## Constructs ## - -We support the following meta programming constructs: - -| `$var id = exp` | Defines a named constant value. `$id` is valid util the end of the current meta lexical block. | -|:----------------|:-----------------------------------------------------------------------------------------------| -| `$range id exp..exp` | Sets the range of an iteration variable, which can be reused in multiple loops later. | -| `$for id sep [[ code ]]` | Iteration. The range of `id` must have been defined earlier. `$id` is valid in `code`. | -| `$($)` | Generates a single `$` character. | -| `$id` | Value of the named constant or iteration variable. | -| `$(exp)` | Value of the expression. | -| `$if exp [[ code ]] else_branch` | Conditional. | -| `[[ code ]]` | Meta lexical block. | -| `cpp_code` | Raw C++ code. | -| `$$ comment` | Meta comment. | - -**Note:** To give the user some freedom in formatting the Pump source -code, Pump ignores a new-line character if it's right after `$for foo` -or next to `[[` or `]]`. Without this rule you'll often be forced to write -very long lines to get the desired output. Therefore sometimes you may -need to insert an extra new-line in such places for a new-line to show -up in your output. - -## Grammar ## - -``` -code ::= atomic_code* -atomic_code ::= $var id = exp - | $var id = [[ code ]] - | $range id exp..exp - | $for id sep [[ code ]] - | $($) - | $id - | $(exp) - | $if exp [[ code ]] else_branch - | [[ code ]] - | cpp_code -sep ::= cpp_code | empty_string -else_branch ::= $else [[ code ]] - | $elif exp [[ code ]] else_branch - | empty_string -exp ::= simple_expression_in_Python_syntax -``` - -## Code ## - -You can find the source code of Pump in [scripts/pump.py](../scripts/pump.py). It is still -very unpolished and lacks automated tests, although it has been -successfully used many times. If you find a chance to use it in your -project, please let us know what you think! We also welcome help on -improving Pump. - -## Real Examples ## - -You can find real-world applications of Pump in [Google Test](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgoogletest\.googlecode\.com) and [Google Mock](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgooglemock\.googlecode\.com). The source file `foo.h.pump` generates `foo.h`. - -## Tips ## - - * If a meta variable is followed by a letter or digit, you can separate them using `[[]]`, which inserts an empty string. For example `Foo$j[[]]Helper` generate `Foo1Helper` when `j` is 1. - * To avoid extra-long Pump source lines, you can break a line anywhere you want by inserting `[[]]` followed by a new line. Since any new-line character next to `[[` or `]]` is ignored, the generated code won't contain this new line. |