These are the data structures used in the symbol tables that get generated by the compiler.

Expression pointers reference values and arguments. All expressions are initially chained onto the "needle" and "thread" lists. The list is evaluated at compile time to obtain constants and then at run time as values are needed. When compiling map expressions they are moved to DDS_MAP (defined in dds_binary.h). Go to the Compiler and Symbol Tables sections for a brief discussion on those topics.

Structures:

DDS_SYM       - Generic symbol Table item 
DDS_TYPE      - Type descriptor (DDS_SYM_TYPE)
DDS_OBJECT    - Object storage descriptor
DDS_MEMBER    - Struct or Unions field descriptor
DDS_EXPR      - Generic expression descriptor (DDS_SYM_EXPR)
DDS_EARG      - Expression argument descriptor
DDS_EXPR1     - Expression descriptor for single argument (DDS_SYM_EXPR)
DDS_EXPR2     - Expression descriptor for two arguments (DDS_SYM_EXPR)
DDS_EXPR3     - Expression descriptor for three arguments (DDS_SYM_EXPR)
DDS_EXPR4     - Expression descriptor for four arguments (DDS_SYM_EXPR)
DDS_EXPRA     - Assignment expression descriptor (DDS_SYM_EXPR)
DDS_EXPRC     - Copy op expression descriptor (DDS_SYM_EXPR)
DDS_VALUE     - Expression descriptor (DDS_SYM_EXPR)
DDS_CONDITION - Conditional op expression descriptor
DDS_BLOCK     - Block descriptor, begins unique name space (DDS_SYM_BLOCK)
DDS_DECLARE   - Parser temporaries for nested declarations
DDS_LABEL     - Label descriptor (DDS_SYM_LABEL)
DDS_RELOC     - Relocation descriptor for pointers within symbol tables
DDS_OPNOTE    - Opcode annotation descriptor
DDS_DUMP_ITEM - Field descriptor in tabular dump list descriptor
DDS_LEX_START - Les start state cjamges
DDS_SCANNER   - Scanner input stack (analogous to nested "#includes")
    

Globals:

DDS_SYM      *dds_push_sym;     /* Temporary for PUSH_SYM and PUSH_VALUE macro */
DDS_DECLARE  *dds_declare;      /* Current declaration scope */
DDS_OPNOTE   *dds_opnote;       /* Opcode descriptor table */
DDS_TABLE     dds_keyword;      /* Parser keyword hash table */
DDS_TABLE    *dds_symbol;       /* Pointer to active symbol table. */
DDS_BLOCK    *dds_block;        /* Pointer to current block in active symbol table. */
DDS_EXPR     *dds_needle;       /* Pointer to first expression to evaluate. */
DDS_EXPR     *dds_thread;       /* Pointer to lst expression to evaluate. */
DDS_BLOCK    *dds_prime_block;  /* Prime block for in symbol table */
DDS_BLOCK    *dds_error_block;  /* Error recovery entries in prime symbol table */
DDS_TYPE     *dds_error_type;   /* Error recovery entries in prime symbol table */
DDS_MEMBER   *dds_error_member; /* Error recovery entries in prime symbol table */
DDS_VALUE    *dds_error_value;  /* Error recovery entries in prime symbol table */
DDS_OBJECT   *dds_error_object; /* Error recovery entries in prime symbol table */
DDS_EXPR     *dds_error_expr;   /* Error recovery entries in prime symbol table */
DDS_EXPR     *dds_error_thread; /* Error recovery entries in prime symbol table */
DDS_SCANNER  *dds_lexer;        /* Handle into scanner state */
DDS_SCANNER   dds_lexer_root;   /* Handle into scanner state */
DDS_LEX_START dds_lex_ss;       /* Lex start state */
DDS_OBJECT   *dds_nop_object;
DDS_EXPRA     DDS_CON_EXPRA;    /* Used to evaluate one conversion */
void        **DDS_PTR_CEMETERY; /* Graveyard for unused pointers computed by expressions. */ 
char         *dds_hist;         /* History dictionary for compiler "hist:" references */
char         *dds_shape_name[]; /* List of deferred shape names for compile error msgs */