The PCalc Polynomial Calculator
		      Users' Guide and Reference

			   P. N. Hilfinger

The Polynomial Calculator (pcalc) provides a simple interface for 
inputting multivariable polynomials, for adding, subtracting, and
multiplying them, for performing substitutions of their variables, and
for simplifying them to a canonical form.  

Input is free format.  A polynomial is written according to the
following BNF:

	<poly> ::= <opt-sign> <term> | <poly> <add operator> <term>
 	<add operator> ::=  "+" | "-"
	<opt-sign> ::=  "-" | 
	<term> ::= <factor> | <term> <factor>
	<factor> ::= <primary> | <primary> "^" <integer constant>
	<factor> ::= <integer constant> | <variable> | "(" <poly> ")" 
		     | <function call>
	<function call> ::= <name> "(" <args> ")" | <name> "(" ")"

	<integer constant> ::= non-negative decimal numeral
	<variable> ::= single lower-case letter
	<name> ::= single upper-case letter
	<args> ::= <poly> | <args> "," <poly>

The <factor>s in a <term> are multipled.  The "^" syntax denotes 
exponentiation.

All integer constants and all coefficients in computed polynomials
must be in the range -2**63 .. 2**63-1, or the results are undefined.
All exponents must be in the range 0 .. 2**31-1.

The possible input commands are as follows:

  #  Arbitrary text
	A one-line comment.

  <poly> ;
	Simplifies and prints <poly>.

  DEF <name> ( <formals> ) = <poly> ;
	Defines the function call <name>(p1,...pn) to be 
	<poly> with p1,...,pn substituted for the variables in <formals> 
	(which is a comma-separated list of 0 or more <variable>s).  
	Only the variables in <formals> may appear in <poly>.

  QUIT 
  EXIT
	Exit the program.

Command input is free-format; commands (other than comments) 
may cross line boundaries, and multiple commands are allowed on a line.

EXAMPLE: 

In the following, input from the terminal is marked with a "> " prompt.

    Pcalc, version 1.0
    > # Computation of aX^3 + bX^2 + cX + d
    > DEF P(x,a,b,c,d) = d+x(c+x(b+ax));
    > P(y,1,-2,3,4);
    = y^3-2y^2+3y+4
    > P(z,0,0,1,2)P(y,1,-2,3,4);
    = y^3z+2y^3-2y^2z-4y^2+3yz+6y+4
    > (y-2)(z+1);
    = yz+y-2z-2
    > P(z,0,0,1,2)-P(z,1,-2,1,4);
    = -z^3+2z^2-2
    > QUIT