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 .TH HOC 1 .SH NAME hoc \- interactive floating point language .SH SYNOPSIS .B hoc [ .I file ... ] [ .B -e .I expression ] .SH DESCRIPTION .I Hoc interprets a simple language for floating point arithmetic, at about the level of BASIC, with C-like syntax and functions. .PP The named .I files are read and interpreted in order. If no .I file is given or if .I file is .L - .I hoc interprets the standard input. The .B -e option allows input to .I hoc to be specified on the command line, to be treated as if it appeared in a file. .PP .I Hoc input consists of .I expressions and .IR statements . Expressions are evaluated and their results printed. Statements, typically assignments and function or procedure definitions, produce no output unless they explicitly call .IR print . .PP Variable names have the usual syntax, including .LR _ ; the name .L _ by itself contains the value of the last expression evaluated. The variables .BR E , .BR PI , .BR PHI , .BR GAMMA and .B DEG are predefined; the last is 59.25..., degrees per radian. .PP Expressions are formed with these C-like operators, listed by decreasing precedence. .TP .B ^ exponentiation .TP .B ! - ++ -- .TP .B * / % .TP .B + - .TP .B > >= < <= == != .TP .B && .TP .B || .TP .B = += -= *= /= %= .PP Built in functions are .BR abs , .BR acos , .BR asin , .B atan (one argument), .BR cos , .BR cosh , .BR exp , .BR int , .BR log , .BR log10 , .BR sin , .BR sinh , .BR sqrt , .BR tan , and .BR tanh . The function .B read(x) reads a value into the variable .B x and returns 0 at EOF; the statement .B print prints a list of expressions that may include string constants such as \fL"hello\en"\f1.\fP .PP Control flow statements are .BR if - else , .BR while , and .BR for , with braces for grouping. Newline ends a statement. Backslash-newline is equivalent to a space. .PP Functions and procedures are introduced by the words .B func and .BR proc ; .B return is used to return with a value from a function. .SH EXAMPLES .EX 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) .EE .SH SOURCE .B \*9/src/cmd/hoc .SH "SEE ALSO" .IR bc (1), .IR dc (1) .br B. W. Kernighan and R. Pike, .I The Unix Programming Environment, Prentice-Hall, 1984 .SH BUGS Error recovery is imperfect within function and procedure definitions.