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diff --git a/impl/antlr/libantlr3c-3.4/doxygen/interop.dox b/impl/antlr/libantlr3c-3.4/doxygen/interop.dox new file mode 100644 index 0000000..3401539 --- /dev/null +++ b/impl/antlr/libantlr3c-3.4/doxygen/interop.dox @@ -0,0 +1,327 @@ +/// \page interop Interacting with the Generated Code +/// +/// \section intro Introduction +/// +/// The main way to interact with the generated code is via action code placed within <code>{</code> and +/// <code>}</code> characters in your rules. In general, you are advised to keep the code you embed within +/// these actions, and the grammar itself to an absolute minimum. Rather than embed code directly in your +/// grammar, you should construct an API, that is called from the actions within your grammar. This way +/// you will keep the grammar clean and maintainable and separate the code generators or other code +/// from the definition of the grammar itself. +/// +/// However, when you wish to call your API functions, or insert small pieces of code that do not +/// warrant external functions, you will need to access elements of tokens, return elements from +/// parser rules and perhaps the internals of the recognizer itself. The C runtime provides a number +/// of MACROs that you can use within your action code. It also provides a number of performant +/// structures that you may find useful for building symbol tables, lists, tries, stacks, arrays and so on (all +/// of which are managed so that your memory allocation problems are minimized.) +/// +/// \section rules Parameters and Returns from Parser Rules +/// +/// The C target does not differ from the Java target in any major ways here, and you should consult +/// the standard documentation for the use of parameters on rules and the returns clause. You should +/// be aware though, that the rules generate C function calls and therefore the input and returns +/// clauses are subject to the constraints of C scoping. +/// +/// You should note that if your parser rule returns more than a single entity, then the return +/// type of the generated rule function is a struct, which is returned by value. This is also the case +/// if your rule is part of a tree building grammar (uses the <code>output=AST;</code> option. +/// +/// Other than the notes above, you can use any pre-declared type as an input or output parameter +/// for your rule. +/// +/// \section memory Memory Management +/// +/// You are responsible for allocating and freeing any memory used by your own +/// constructs, ANTLR will track and release any memory allocated internally for tokens, trees, stacks, scopes +/// and so on. This memory is returned to the malloc pool when you call the free method of any +/// ANTLR3 produced structure. +/// +/// For performance reasons, and to avoid thrashing the malloc allocation system, memory for amy elements +/// of your generated parser is allocated in chunks and parcelled out by factories. For instance memory +/// for tokens is created as an array of tokens, and a token factory hands out the next available slot +/// to the lexer. When you free the lexer, the allocated memory is returned to the pool. The same applies +/// to 'strings' that contain the token text and various other text elements accessed within the lexer. +/// +/// The only side effect of this is that after your parse and analysis is complete, if you wish to retain +/// anything generated automatically, you must copy it before freeing the recognizer structures. In practice +/// it is usually practical to retain the recognizer context objects until your processing is complete or +/// to use your own allocation scheme for generating output etc. +/// +/// The advantage of using object factories is of course that memory leaks and accessing de-allocated +/// memory are bugs that rarely occur within the ANTLR3 C runtime. Further, allocating memory for +/// tokens, trees and so on is very fast. +/// +/// \section ctx The CTX Macro +/// +/// The CTX macro is a fundamental parameter that is passed as the first parameter to any generated function +/// concerned with your lexer, parser, or tree parser. The is is the context pointer for your generated +/// recognizer and is how you invoke the generated functions, and access the data embedded within your generated +/// recognizer. While you can use it to directly access stacks, scopes and so on, this is not really recommended +/// as you should use the $xxx references that are available generically within ANTLR grammars. +/// +/// The context pointer is used because this removes the need for any global/static variables at all, either +/// within the generated code, or the C runtime. This is of course fundamental to creating free threading +/// recognizers. Wherever a function call or rule call required the ctx parameter, you either reference it +/// via the CTX macro, or the ctx parameter is in fact the return type from calling the 'constructor' +/// function for your parser/lexer/tree parser (see code example in "How to build Generated Code" .) +/// +/// \section macros Pre-Defined convenience MACROs +/// +/// While the author is not fond of using C MACROs to hide code or structure access, in the case of generated +/// code, they serve two useful purposes. The first is to simplify the references to internal constructs, +/// the second is to facilitate the change of any internal interface without requiring you to port grammars +/// from earlier versions (just regenerate and recompile). As of release 3.1, these macros are stable and +/// will only change their usage interface in the event of bugs being discovered. You are encouraged to +/// use these macros in your code, rather than access the raw interface. +/// +/// \bNB: Macros that act like statements must be terminated with a ';'. The macro body does not +/// supply this, nor should it. Macros that call functions are declared with () even if they +/// have no parameters, macros that reference fields do not have a () declaration. +/// +/// \section lexermacros Lexer Macros +/// +/// There are a number of macros that are useful exclusively within lexer rules. There are additional +/// macros, common to all recognizer, and these are documented in the section Common Macros. +/// +/// \subsection lexer LEXER +/// +/// The <code>LEXER</code> macro returns a pointer to the base lexer object, which is of type #pANTLR3_LEXER. This is +/// not the pointer to your generated lexer, which is supplied by the CTX macro, +/// but to the common implementation of a lexer interface, +/// which is supplied to all generated lexers. +/// +/// \subsection lexstate LEXSTATE +/// +/// Provides a pointer to the lexer shared state structure, which is where the tokens for a +/// rule are constructed and the status elements of the lexer are kept. This pointer is of type +/// #pANTLR3_RECOGNIZER_SHARED_STATE.In general you should only access elements of this structure +/// if there is not already another MACRO or standard $xxxx antlr reference that refers to it. +/// +/// \subsection la LA(n) +/// +/// The <code>LA</code> macro returns the character at index n from the current input stream index. The return +/// type is #ANTLR3_UINT32. Hence <code>LA(1)</code> returns the character at the current input position (the +/// character that will be consumed next), <code>LA(-1)</code> returns the character that has just been consumed +/// and so on. The <code>LA(n)</code> macro is useful for constructing semantic predicates in lexer rules. The +/// reference <code>LA(0)</code> is undefined and will cause an error in your lexer. +/// +/// \subsection getcharindex GETCHARINDEX() +/// +/// The <code>GETCHARINDEX</code> macro returns the index of the current character position as a 0 based +/// offset from the start of the input stream. It returns a value type of #ANTLR3_UINT32. +/// +/// \subsection getline GETLINE() +/// +/// The <code>GETLINE</code> macro returns the line number of current character (<code>LA(1)</code> in the input +/// stream. It returns a value type of #ANTLR3_UINT32. Note that the line number is incremented +/// automatically by an input stream when it sees the input character '\n'. The character that causes +/// the line number to increment can be changed by calling the SetNewLineChar() method on the input +/// stream before invoking the lexer and after creating the input stream. +/// +/// \subsection gettext GETTEXT() +/// +/// The <code>GETTEXT</code> macro returns the text currently matched by the lexer rule. In general you should use the +/// generic $text reference in ANTLR to retrieve this. The return type is a reference type of #pANTLR3_STRING +/// which allows you to manipulate the text you have retrieved (\b NB this does not change the input stream +/// only the text you copy from the input stream when you use this MACRO or $text). +/// +/// The reference $text->chars or GETTEXT()->chars will reference a pointer to the '\\0' terminated character +/// string that the ANTLR3 #pANTLR3_STRING represents. String space is allocated automatically as well as +/// the structure that holds the string. The #pANTLR3_STRING_FACTORY associated with the lexer handles this +/// and when you close the lexer, it will automatically free any space allocated for strings and their structures. +/// +/// \subsection getcharpositioninline GETCHARPOSITIONINLINE() +/// +/// The <code>GETCHARPOSITIONINLINE</code> returns the zero based offset of character <code>LA(1)</code> +/// from the start of the current input line. See the macro <code>GETLINE</code> for details on what the +/// line number means. +/// +/// \subsection emit EMIT() +/// +/// The macro <code>EMIT</code> causes the text range currently matched to the lexer rule to be emitted +/// immediately as the token for the rule. Subsequent text is matched but ignored. The type used for the +/// the token is the name of the lexer rule or, if you have change this by using $type = XXX;, the type +/// XXX is used. +/// +/// \subsection emitnew EMITNEW(t) +/// +/// The macro <code>EMITNEW</code> causes the supplied token reference <code>t</code> to be used as the +/// token emitted by the rule. The parameter <code>t </code> must be of type #pANTLR3_COMMON_TOKEN. +/// +/// \subsection index INDEX() +/// +/// The <code>INDEX</code> macro returns the current input position according to the input stream. It is not +/// guaranteed to be the character offset in the input stream but is instead used as a value +/// for marking and rewinding to specific points in the input stream. Use the macro <code>GETCHARINDEX()</code> +/// to find out the position of the <code>LA(1)</code> in the input stream. +/// +/// \subsection pushstream PUSHSTREAM(str) +/// +/// The <code>PUSHSTREAM</code> macro, in conjunction with the <code>POPSTREAM</code> macro (called internally in the runtime usually) +/// can be used to stack many input streams to the lexer, and implement constructs such as the C pre-processor +/// \#include directive. +/// +/// An input stream that is pushed on to the stack becomes the current input stream for the lexer and +/// the state of the previous stream is automatically saved. The input stream will be automatically +/// popped from the stack when it is exhausted by the lexer. You may use the macro <code>POPSTREAM</code> +/// to return to the previous input stream prior to exhausting the currently stacked input stream. +/// +/// Here is an example of using the macro in a lexer to implement the C \#include pre-processor directive: +/// +/// \code +/// fragment +/// STRING_GUTS : (~('\\'|'"') )* ; +/// +/// LINE_COMMAND +/// : '#' (' ' | '\t')* +/// ( +/// 'include' (' ' | '\t')+ '"' file = STRING_GUTS '"' (' ' | '\t')* '\r'? '\n' +/// { +/// pANTLR3_STRING fName; +/// pANTLR3_INPUT_STREAM in; +/// +/// // Create an initial string, then take a substring +/// // We can do this by messing with the start and end +/// // pointers of tokens and so on. This shows a reasonable way to +/// // manipulate strings. +/// // +/// fName = $file.text; +/// printf("Including file '\%s'\n", fName->chars); +/// +/// // Create a new input stream and take advantage of built in stream stacking +/// // in C target runtime. +/// // +/// in = antlr38BitFileStreamNew(fName->chars); +/// PUSHSTREAM(in); +/// +/// // Note that the input stream is not closed when it EOFs, I don't bother +/// // to do it here, but it is up to you to track streams created like this +/// // and destroy them when the whole parse session is complete. Remember that you +/// // don't want to do this until all tokens have been manipulated all the way through +/// // your tree parsers etc as the token does not store the text it just refers +/// // back to the input stream and trying to get the text for it will abort if you +/// // close the input stream too early. +/// // +/// +/// } +/// | (('0'..'9')=>('0'..'9'))+ ~('\n'|'\r')* '\r'? '\n' +/// ) +/// {$channel=HIDDEN;} +/// ; +/// \endcode +/// +/// \subsection popstream POPSTREAM() +/// +/// Assuming that you have stacked an input stream using the PUSHSTREAM macro, you can +/// remove it from the stream stack and revert to the previous input stream. You should be careful +/// to pop the stream at an appropriate point in your lexer action, so you do not match characters +/// from one stream with those from another in the same rule (unless this is what you want to do) +/// +/// \subsection settext SETTEXT(str) +/// +/// A token manufactured by the lexer does not actually physically store the text from the +/// input stream to which it matches. The token string is instead created only if you ask for +/// the text. However if you wish to change the text that the token represents you can use +/// this macro to set it explicitly. Note that this does not change the input stream text +/// but associates the supplied #pANTLR3_STRING with the token. This string is then returned +/// when parser and tree parser reference the tokens via the $xxx.text reference. +/// +/// \subsection user1 USER1 USER2 USER3 and CUSTOM +/// +/// While you can create your own custom token class and have the lexer deal with this, this +/// is a lot of work compared to the trivial inheritance that can be achieved in the Java target. +/// In many cases though, all that is needed is the addition of a few data items such as an +/// integer or a pointer. Rather than require C programmers to create complicated structures +/// just to add a few data items, the C target provides a few custom fields in the standard +/// token, which will fulfil the needs of most lexers and parsers. +/// +/// The token fields user1, user2, and user3 are all value types of #ANTLR_UINT32. In the +/// parser you can reference these fields directly from the token: <code>x=TOKNAME { $x->user1 ...</code> +/// but when you are building the token in the lexer, you must assign to the fields using the +/// macros <code>USER1</code>, <code>USER2</code>, or <code>USER3</code>. As in: +/// +/// \code +/// LEXTOK: 'AAAAA' { USER1 = 99; } ; +/// \endcode +/// +/// +/// \section parsermacros Parser and Tree Parser Macros +/// +/// \subsection parser PARSER +/// +/// The <code>PARSER</code> macro returns a pointer to the base parser or tree parser object, which is of type #pANTLR3_PARSER +/// or #pANTLR3_TREE_PARSER . This is not the pointer to your generated parser, which is supplied by the <code>CTX</code> macro, +/// but to the common implementation of a parser or tree parser interface, which is supplied to all generated parsers. +/// +/// \subsection index INDEX() +/// +/// When used in the parser, the <code>INDEX</code> macro returns the position of the current +/// token ( LT(1) ) in the input token stream. It can be used for <code>MARK</code> and <code>REWIND</code> +/// operations. +/// +/// \subsection lt LT(n) and LA(n) +/// +/// In the parser, the macro <code>LT(n)</code> returns the #pANTLR3_COMMON_TOKEN at offset <code>n</code> from +/// the current token stream input position. The macro <code>LA(n)</code> returns the token type of the token +/// at position <code>n</code>. The value <code>n</code> cannot be zero, and such a reference will return +/// <code>NULL</code> and possibly cause an error. <code>LA(1)</code> is the token that is about to be +/// recognized and <code>LA(-1)</code> is the token that has just been recognized. Values of n that exceed the +/// limits of the token stream boundaries will return <code>NULL</code>. +/// +/// \subsection psrstate PSRSTATE +/// +/// Returns the shared state pointer of type #pANTLR3_RECOGNIZER_SHARED_STATE. This is not generally +/// useful to the grammar programmer as the useful elements have generic $xxx references built in to +/// ANTLR. +/// +/// \subsection adaptor ADAPTOR +/// +/// When building an AST via a parser, the work of constructing and manipulating trees is done +/// by a supplied adaptor class. The default class is usually fine for most tree operations but +/// if you wish to build your own specialized linked/tree structure, then you may need to reference +/// the adaptor you supply directly. The <code>ADAPTOR</code> macro returns the reference to the tree adaptor +/// which is always of type #pANTLR3_BASE_TREE_ADAPTOR, even if it is your custom adapter. +/// +/// \section commonmacros Macros Common to All Recognizers +/// +/// \subsection recognizer RECOGNIZER +/// +/// Returns a reference type of #pANTRL3_BASE_RECOGNIZER, which is the base functionality supplied +/// to all recognizers, whether lexers, parsers or tree parsers. You can override methods in this +/// interface by installing your own function pointers (once you know what you are doing). +/// +/// \subsection input INPUT +/// +/// Returns a reference to the input stream of the appropriate type for the recognizer. In a lexer +/// this macro returns a reference type of #pANTLR3_INPUT_STREAM, in a parser this is type +/// #pANTLR3_TOKEN_STREAM and in a tree parser this is type #pANTLR3_COMMON_TREE_NODE_STREAM. +/// You can of course provide your own implementations of any of these interfaces. +/// +/// \subsection mark MARK() +/// +/// This macro will cause the input stream for the current recognizer to be marked with a +/// checkpoint. It will return a value type of #ANTLR3_MARKER which you can use as the +/// parameter to a <code>REWIND</code> macro to return to the marked point in the input. +/// +/// If you know you will only ever rewind to the last <code>MARK</code>, then you can ignore the return +/// value of this macro and just use the <code>REWINDLAST</code> macro to return to the last <code>MARK</code> that +/// was set in the input stream. +/// +/// \subsection rewind REWIND(m) +/// +/// Rewinds the appropriate input stream back to the marked checkpoint returned from a prior +/// MARK macro call and supplied as the parameter <code>m</code> to the <code>REWIND(m)</code> +/// macro. +/// +/// \subsection rewindlast REWINDLAST() +/// +/// Rewinds the current input stream (character, tokens, tree nodes) back to the last checkpoint +/// marker created by a <code>MARK</code> macro call. Fails silently if there was no prior +/// <code>MARK</code> call. +/// +/// \subsection seek SEEK(n) +/// +/// Causes the input stream to position itself directly at offset <code>n</code> in the stream. Works for all +/// input stream types, both lexer, parser and tree parser. +/// |