package rebelsky.compiler.pascal;

import java.util.Vector;
import rebelsky.compiler.parser.Nonterminal;

/**
 * A collection of constants that define the nonterminals in Pascal.
 * (Not yet complete.)
 *
 * @author Samuel A. Rebelsky
 * @version 0.6 of November 2002
 */

public class PascalNonterminals
{
  // +-----------+-----------------------------------------------------------
  // | Constants |
  // +-----------+

  /** 
   * An addition operator, such as plus or minus. 
   */
  public static final Nonterminal ADDING_OPERATOR =
    new Nonterminal("adding_operator");

  /** 
   * An assignment statement. 
   */
  public static final Nonterminal ASSIGNMENT =
    new Nonterminal("assignment");

  /** 
   * A list of assignment statements.  Not used in the standard
   * Pascal grammar, but useful for some variant grammars that
   * I like to create.
   *
   * <assignment_list> ::= <assignment> TSEMI { <assignment> TSEMI }
   */
  public static final Nonterminal ASSIGNMENT_LIST =
    new Nonterminal("assignment_list");

  /**
   * A block of code.  In Pascal, lots of declarations followed by
   * a group of statements enclosed in begin and end.
   */
  public static final Nonterminal BLOCK =
    new Nonterminal("block");

  /**
   * A Boolean expression.  Not part of standard Pascal, but useful
   * in a number of variants.
   */
  public static final Nonterminal BOOLEAN_EXPRESSION =
    new Nonterminal("boolean_expression");

  /**
   * A compound statment (a list of statements enclosed in a begin/end pair).
   */
  public static final Nonterminal COMPOUND_STATEMENT =
    new Nonterminal("compound_statement");
  
  /*
   * A conditional statement (e.g., an if statement).
   */
  public static final Nonterminal CONDITIONAL =
    new Nonterminal("conditional");
    
  /**
   * A constant.
   */
  public static final Nonterminal CONSTANT =
    new Nonterminal("constant");

  /**
   * A single constant definition.
   */
  public static final Nonterminal CONSTANT_DEFINITION =
    new Nonterminal("constant_definition");

  /**
   * Zero or more constant definitions.
   */
  public static final Nonterminal CONSTANT_DEFINITIONS =
    new Nonterminal("constant_definitions");

  /**
   * The famous expression.
   */
  public static final Nonterminal EXPRESSION  =
    new Nonterminal("expression");

  /**
   * Part of an expression.  Factors contain no unparenthesized
   * addition and multiplication symbols.
   */
  public static final Nonterminal FACTOR =
    new Nonterminal("factor");

  /**
   * An identifier that names a file.  Used in the program heading.
   */
  public static final Nonterminal FILE_IDENTIFIER  =
    new Nonterminal("file_identifier");

  /**
   * A call to a function.
   */
  public static final Nonterminal FUNCTION_CALL =
    new Nonterminal("function_call");
    
  /**
   * The declaration of one function.  Typically gives parameters (with
   * types, return value, local variables, and body.
   */
  public static final Nonterminal FUNCTION_DECLARATION =
    new Nonterminal("function_declaration");
    
  /**
   * A list of function declarations.  Not standard Pascal, but useful
   * in some variant languages.
   */
  public static final Nonterminal FUNCTION_DECLARATIONS =
    new Nonterminal("function_declarations");
    
  /**
   * A non-empty list of identifiers.
   */
  public static final Nonterminal IDENTIFIER_LIST =
    new Nonterminal("identifier_list");

  /**
   * A label, typically used as the destination of a (blech) goto
   * statement.
   */
  public static final Nonterminal LABEL =
    new Nonterminal("label");

  /**
   * The declaration of zero or more labels that are to be used
   * within a block.
   */
  public static final Nonterminal LABEL_DECLARATION =
    new Nonterminal("label_declaration");

  /** 
   * An operator with the precedence of multiplication, such as 
   * multiplication, division, or modulus.
   */
  public static final Nonterminal MULTIPLYING_OPERATOR =
    new Nonterminal("multiplying_operator");

  /**
   * A call to a procedure.  Not to be confused with a function call
   * or with a procedure declaration.
   */
  public static final Nonterminal PROCEDURE_CALL =
    new Nonterminal("procedure_call");
  
  /**
   * A complete program.  Typically the start symbol of the grammar.
   */
  public static final Nonterminal PROGRAM =
    new Nonterminal("program");

  /**
   * The heading of a program.  Gives name, input, and output.
   */
  public static final Nonterminal PROGRAM_HEADING =
    new Nonterminal("program_heading");

  /**
   * Relational operators, used for comparing values.
   */
  public static final Nonterminal RELATIONAL_OPERATOR =
    new Nonterminal("relational_opeator");

  /**
   * A statement.
   */
  public static final Nonterminal STATEMENT =
    new Nonterminal("statement");
    
  /**
   * Part of an expression.  Terms are expression with no unparenthesized
   * additive operations.
   */
  public static final Nonterminal TERM =
    new Nonterminal("term");

  /**
   * The name of a type.
   */
  public static final Nonterminal TYPE_IDENTIFIER =
    new Nonterminal("type_identifier");

  /**
   * A non-negative number.
   */
  public static final Nonterminal UNSIGNED_NUMBER =
    new Nonterminal("unsigned_number");

  /**
   * A variable (something that can be assigned to).
   */
  public static final Nonterminal VARIABLE =
    new Nonterminal("variable");

  /**
   * Declare the type of one or more variables.
   */
  public static final Nonterminal VARIABLE_DECLARATION =
    new Nonterminal("variable_declaration");

  /**
   * Zero or more variable declarations.
   */
  public static final Nonterminal VARIABLE_DECLARATIONS =
    new Nonterminal("variable_declarations");

  /**
   * A while loop.
   */
  public static final Nonterminal WHILE_LOOP =
    new Nonterminal("while_loop");
} // class PascalNonterminals