sjm.examples.sling
Class SlingParser

java.lang.Object
  |
  +--sjm.examples.sling.SlingParser

public class SlingParser

extends java.lang.Object

This class provides a parser for Sling, an imperative language that plots the path of a sling stone.

The grammar this class supports is:

 
 statements    = statement statement*;
 statement     = assignment | forStatement | plotStatement;
 assignment    = variable '=' expression ';' ; 
 plotStatement = "plot" expression ';';
 forStatement  = 
     "for" '(' variable ',' expression ',' expression  ')' 
     '{' statements '}';
 

 variable   = Word;
 

 expression       = term (plusTerm | minusTerm)*;
 plusTerm         = '+' term;
 minusTerm        = '-' term;
 term             = element (timesElement | divideElement |
                             remainderElement)*;
 timesElement     = '*' element;
 divideElement    = '/' element;
 remainderElement = '%' element;
 element          = '(' expression ')' | baseElement | 
                    negative;
 

 negative    = '-' baseElement; 
 

 baseElement = 
     Num | "pi" | "random" | "s1" | "s2" | "t" | variable | 
     oneArg("abs")    | oneArg("ceil")       | 
     oneArg("cos")    | oneArg("floor")      | 
     oneArg("sin")    | oneArg("tan")        |
     twoArgs("polar") | twoArgs("cartesian") | 
     twoArgs("scale") | twoArgs("sling");
 

 oneArg(i)  = i '(' expression ')';
 twoArgs(i) = i '(' expression ',' expression ')';
 
 

The following program describes about 10,000 interesting plots:

     plot sling(1, 1) + sling(s1, 100*s2);
 

The class SlingIde provides an interactive development environment for Sling.

Field Summary

protected Alternation	baseElement
protected Sequence	expression
protected Alternation	statement
protected Tokenizer	tokenizer
protected WordOrReservedState	wors

Constructor Summary

SlingParser()

Method Summary

protected Parser	assignment()
protected Parser	baseElement()
protected static Parser	comma()
protected Track	divideElement()
protected Parser	element()
protected Parser	expression()
protected Parser	forStatement()
protected static Parser	lBrace()
protected static Parser	lParen()
protected Track	minusTerm()
protected Parser	negative()
protected Parser	noArgs(java.lang.String name, SlingFunction f)
protected Parser	num()
protected Parser	oneArg(java.lang.String name, SlingFunction f)
protected Parser	pi()
protected Parser	plotStatement()
protected Track	plusTerm()
protected static Parser	rBrace()
protected Track	remainderElement()
protected ReservedLiteral	reserve(java.lang.String s)
protected static Parser	rParen()
protected Parser	s1()
protected Parser	s2()
protected Parser	scale()
protected static Parser	semicolon()
Parser	start()
protected Parser	statement()
protected Parser	statements()
protected Parser	term()
protected Track	timesElement()
Tokenizer	tokenizer() Creates a tokenizer that uses a WordOrReservedState instead of a normal WordState.
protected Parser	twoArg(java.lang.String name, SlingFunction f)
protected Parser	variable()
protected WordOrReservedState	wors()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

expression

protected Sequence expression

statement

protected Alternation statement

baseElement

protected Alternation baseElement

wors

protected WordOrReservedState wors

tokenizer

protected Tokenizer tokenizer

Constructor Detail

SlingParser

public SlingParser()

Method Detail

assignment

protected Parser assignment()

baseElement

protected Parser baseElement()

comma

protected static Parser comma()

divideElement

protected Track divideElement()

element

protected Parser element()

expression

protected Parser expression()

forStatement

protected Parser forStatement()

lBrace

protected static Parser lBrace()

lParen

protected static Parser lParen()

minusTerm

protected Track minusTerm()

negative

protected Parser negative()

noArgs

protected Parser noArgs(java.lang.String name,
                        SlingFunction f)

num

protected Parser num()

oneArg

protected Parser oneArg(java.lang.String name,
                        SlingFunction f)

pi

protected Parser pi()

plotStatement

protected Parser plotStatement()

plusTerm

protected Track plusTerm()

rBrace

protected static Parser rBrace()

remainderElement

protected Track remainderElement()

reserve

protected ReservedLiteral reserve(java.lang.String s)

rParen

protected static Parser rParen()

s1

protected Parser s1()

s2

protected Parser s2()

scale

protected Parser scale()

semicolon

protected static Parser semicolon()

start

public Parser start()

statement

protected Parser statement()

statements

protected Parser statements()

term

protected Parser term()

timesElement

protected Track timesElement()

tokenizer

public Tokenizer tokenizer()

Creates a tokenizer that uses a WordOrReservedState instead of a normal WordState.

twoArg

protected Parser twoArg(java.lang.String name,
                        SlingFunction f)

variable

protected Parser variable()

wors

protected WordOrReservedState wors()