This is CORBA::IDLtree, a module that builds abstract syntax trees from CORBA IDL. The main export is sub Parse_File which takes an IDL input file name as the parameter, and returns a reference to an array of references to the root nodes constructed (or 0 if there were syntax errors.) Parse_File uses two auxiliary data structures: @include_path - Paths where to look for included IDL files %defines - Symbol definitions for the preprocessor (cf. the -D switch on many C compilers) where -DSYM=VAL is represented as $defines{SYM} = VAL. -DSYM is represented as $defines{SYM} = 1. A further export is the sub Dump_Symbols which takes the return value of Parse_File as the parameter, and prints the trees constructed to stdout in IDL syntax. ----------------------------------------------------------------------------- SYMBOL TREE STRUCTURE The following description of the structure of the symbol tree applies to CORBA::IDLtree versions >= 1.0. The structure has been changed w.r.t. previous releases, for example the INTERFACE node now has an "abstract" flag. Also, all the scalars used as constants, e.g. $INTERFACE, have been changed to subroutines, e.g. &INTERFACE, to better express the constness of these values. However, it is intended to keep further changes to the user interface to a minimum, i.e. the IDLtree programming interface is now considered stable. A "thing" in the symbol tree can be either a reference to a node, or a reference to an array of references to nodes. A node is a five-element array with the elements [0] => TYPE (MODULE|INTERFACE|STRUCT|UNION|ENUM|TYPEDEF...) [1] => NAME [2] => SUBORDINATES [3] => COMMENT (introduced in IDLtree version 1.2) [4] => SCOPEREF Some IDL types are representable as a simple numeric constant; they do not require nodes. We'll call these types "elementary". Elementary types are the scalar types, e.g. boolean, short, unsigned long long, any, string. Other IDL types cannot be represented in this way, they require more information. An enum, for example, requires the enumeration literals. These types are represented as nodes. The TYPE element contains a numeric ID identifying what IDL type the node represents. The NAME element, unless specified otherwise, simply holds the name string of the respective IDL syntactic item. The SUBORDINATES element depends on the node type. Sometimes an item in the SUBORDINATES may contain either a type ID or a reference to the defining node; we will call that a `type descriptor'. Which of the two alternatives is in effect can be determined via the isnode() function. Contents of SUBORDINATES: MODULE or Reference to an array of nodes (symbols) which are defined INTERFACE within the module or interface. In the case of INTERFACE, element [0] in this array will contain a reference to a further array which in turn contains references to the parent interface(s) if inheritance is used, or the null value if the current interface is not derived by inheritance. Element [1] is the "abstract" flag which is non-zero for interfaces declared abstract. INTERFACE_FWD Reference to the node of the full interface declaration. STRUCT or Reference to an array of node references representing the EXCEPTION member components of the struct or exception. Each member representative node is a quadruplet consisting of (TYPE, NAME, , COMMENT). The is a reference to a list of dimension numbers, or is 0 if no dimensions were given. UNION Similar to STRUCT/EXCEPTION, reference to an array of nodes. For union members, the member node has the same structure as for STRUCT/EXCEPTION. However, the first node contains a type descriptor for the discriminant type. The TYPE of a member node may also be CASE or DEFAULT. For CASE, the NAME is unused, and the SUBORDINATE contains a reference to a list of the case values for the following member node. For DEFAULT, both the NAME and the SUBORDINATE are unused. ENUM Reference to the array of enum value literals. If the global variable $enable_enum_comments is set then the elements in the array may be shaped differently: - If the enum literal is not followed by a comment then the element in the array is the enum literal as usual. - If the enum literal is followed by a comment then the element in the array is a reference to a tuple. In this tuple, the first element is the enum literal, and the second element is a reference to the comment list. Thus, when generating code for the literals, it is recommended to use the `ref' predicate to find out which of the two alternatives is in effect for each array element. TYPEDEF Reference to a two-element array: element 0 contains a reference to the type descriptor of the original type; element 1 contains a reference to an array of dimension numbers, or the null value if no dimensions are given. SEQUENCE As a special case, the NAME element of a SEQUENCE node does not contain a name (as sequences are anonymous types), but instead is used to hold the bound number. If the bound number is 0, then it is an unbounded sequence. The SUBORDINATES element contains the type descriptor of the base type of the sequence. This descriptor could itself be a reference to a SEQUENCE defining node (that is, a nested sequence definition.) Bounded strings are treated as a special case of sequence. They are represented as references to a node that has BOUNDED_STRING or BOUNDED_WSTRING as the type ID, the bound number in the NAME, and the SUBORDINATES element is unused. CONST Reference to a two-element array. Element 0 is a type descriptor of the const's type; element 1 is a reference to an array containing the RHS expression symbols. FIXED Reference to a two-element array. Element 0 contains the digit number and element 1 contains the scale factor. The NAME component in a FIXED node is unused. VALUETYPE [0] => $is_abstract (boolean) [1] => reference to a tuple (two-element list) containing inheritance related information: [0] => $is_truncatable (boolean) [1] => \@ancestors (reference to array containing references to ancestor nodes) [2] => \@members: reference to array containing references to tuples (two-element lists) of the form: [0] => 0|PRIVATE|PUBLIC A zero for this value means the element [1] contains a reference to a METHOD or ATTRIBUTE. In case of METHOD, the first element in the method node subordinates (i.e., the return type) may be FACTORY. [1] => reference to the defining node. In case of PRIVATE or PUBLIC state member, the defining node is the same as for STRUCT subordinates, namely a quadruplet containing: [0] => member type id [1] => member name [2] => dimref (reference to dimensions list) [3] => COMMENT element VALUETYPE_BOX Reference to the defining type node. VALUETYPE_FWD Subordinates unused. NATIVE Subordinates unused. ATTRIBUTE Reference to a two-element array; element 0 is the read- only flag (0 for read/write attributes), element 1 is a type descriptor of the attribute's type. METHOD Reference to a variable length array; element 0 is a type descriptor for the return type. Elements 1 and following are references to parameter descriptor nodes with the following structure: elem. 0 => parameter type descriptor elem. 1 => parameter name elem. 2 => parameter mode (IN, OUT, or INOUT) The last element in the variable-length array is a reference to the "raises" list. This list contains references to the declaration nodes of exceptions raised, or is empty if there is no "raises" clause. INCFILE Reference to an array of nodes (symbols) which are defined within the include file. The Name element of this node contains the include file name. PRAGMA_PREFIX Subordinates unused. PRAGMA_VERSION Version string. PRAGMA_ID ID string. PRAGMA This is for the general case of pragmas that are none of the above, i.e. pragmas unknown to IDLtree. The NAME holds the pragma name, and SUBORDINATES holds a reference to all further text appearing after the pragma name, if any. REMARK The SUBORDINATES of the node is unused. The NAME component contains a reference to a list of comment lines. In the case of a single-line comment, the list will contain only one element; in case of multi- line comments, each line is represented by a list entry. The lines in this list are not newline terminated; empty entries represent empty comment lines. The COMMENT element holds the comment text that follows the IDL declaration on the same line. Usually this is just a single line. However, if a multi- line comment is started on the same line after a declaration, the multi-line comment may extend to further lines - therefore we use a list of lines. The lines in this list are not newline terminated. The COMMENT field is a reference to this list, or contains the value 0 if no comment is present at the IDL item. The SCOPEREF element is a reference back to the node of the module or interface enclosing the current node. If the current node is already at the global scope level, then the SCOPEREF is 0. If the current node is inside an INCFILE, the SCOPEREF element points to the corresponding INCFILE node (the INCFILE reference was introduced in IDLtree version 1.3.) All nodes have this element except for the parameter nodes of methods and the component nodes of structs/unions/exceptions. -- Last updated: 2003/07/25 -- okellogg@users.sourceforge.net