NAME

       hoc - interactive floating point language

SYNOPSIS

       hoc [ file ...  ] [ -e expression ]

DESCRIPTION

       Hoc  interprets  a  simple  language  for floating point arithmetic, at about the level of
       BASIC, with C-like syntax and functions.

       The named files are read and interpreted in order.  If no file is given or if file is  hoc
       interprets  the  standard input.  The -e option allows input to hoc to be specified on the
       command line, to be treated as if it appeared in a file.

       Hoc input consists of expressions and statements.  Expressions  are  evaluated  and  their
       results printed.  Statements, typically assignments and function or procedure definitions,
       produce no output unless they explicitly call print.

       Variable names have the usual syntax, including the name by itself contains the  value  of
       the  last  expression  evaluated.  The variables E, PI, PHI, GAMMA and DEG are predefined;
       the last is 59.25..., degrees per radian.

       Expressions are formed with these C-like operators, listed by decreasing precedence.

       ^      exponentiation

       ! - ++ --

       * / %

       + -

       > >= < <= == !=

       &&

       ||

       = += -= *= /= %=

       Built in functions are abs, acos, asin, atan (one argument), cos,  cosh,  exp,  int,  log,
       log10,  sin,  sinh,  sqrt,  tan,  and  tanh.   The function read(x) reads a value into the
       variable x and returns 0 at EOF; the statement print prints a list of expressions that may
       include string constants such as "hello\n".

       Control  flow  statements  are if-else, while, and for, with braces for grouping.  Newline
       ends a statement.  Backslash-newline is equivalent to a space.

       Functions and procedures are introduced by the words func and  proc;  return  is  used  to
       return with a value from a function.

EXAMPLES

       func gcd(a, b) {
            temp = abs(a) % abs(b)
            if(temp == 0) return abs(b)
            return gcd(b, temp)
       }
       for(i=1; i<12; i++) print gcd(i,12)

SOURCE

       /src/cmd/hoc

SEE ALSO

       bc(1), dc(1)
       B. W. Kernighan and R. Pike, The Unix Programming Environment, Prentice-Hall, 1984

BUGS

       Error recovery is imperfect within function and procedure definitions.

                                                                                      HOC(1plan9)