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Let's use c++/glr to demonstrate custom error messages in C++ (not just in glr2.cc). * examples/c++/glr/c++-types.yy (report_syntax_error): New. * examples/c++/glr/c++-types.test: Adjust. * examples/c/bistromathic/parse.y: Comment changes. * tests/local.at (AT_YYERROR_DEFINE(c++)): Use a nicer way to print the lookakead's name.
69 lines
2.3 KiB
Markdown
69 lines
2.3 KiB
Markdown
# Examples in C++
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This directory contains examples of Bison grammar files in C++.
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You can run `make` to compile these examples. And `make clean` to tidy
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afterwards.
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## simple.yy - Simple example in C++14
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A very simple example in C++, based on variants and symbol constructors.
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Variants allow to use any C++ type as semantic value type, and symbol
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constructors ensure consistency between declared token kind and effective
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semantic value.
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Run as `./simple`.
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Extracted from the documentation: [A Simple C++
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Example](https://www.gnu.org/software/bison/manual/html_node/A-Simple-C_002b_002b-Example.html).
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## variant.yy - Self-contained example in C++98
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A variation of simple.yy, in C++98.
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Run as `./variant`.
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## variant-11.yy - Self-contained example in modern C++
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Another variation of simple.yy, closely related to the previous one, but
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exhibiting support for C++11's move semantics.
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Run as `./variant` or `./variant NUMBER`.
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## calc++ - A Complete C++ Example
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A fully featured C++ version of the canonical example for parsers: a
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calculator. Also uses Flex for the scanner.
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Don't look at this example first: it is fully featured and can serve as a
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starting point for a clean parser in C++. The previous examples are better
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introductory examples, and the C examples are also useful introductory
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examples.
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Extracted from the documentation: [A Complete C++
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Example](https://www.gnu.org/software/bison/manual/html_node/A-Complete-C_002b_002b-Example.html).
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## glr
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This example demonstrates the use of GLR parsers to handle (local)
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ambiguities in the C++ language. See the node "Merging GLR Parses" in
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Bison's documentation.
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It uses (Bison) variants to store objects as semantic values. It also
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demonstrates custom error messages in C++.
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<!---
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Local Variables:
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fill-column: 76
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ispell-dictionary: "american"
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End:
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Copyright (C) 2018-2021 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with no
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Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
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Texts. A copy of the license is included in the "GNU Free
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Documentation License" file as part of this distribution.
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LocalWords: mfcalc calc parsers yy ispell american
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--->
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