Literal strings must be enclosed in double quotes (") or dollar signs
($). With eukleides, enclosing characters yield no difference
but with euktopst dollar signs are taken as part of the string.
Literal strings may be split in several lines.
%nNewline (LF).
%rReturn (CR).
%tTab.
%"Double quote (when enclosing character).
%$Dollar sign (when enclosing character).
%%Percent sign.
length(s)Length of string s.
sub(s, i, j)Substring of string s from index i to j. Indices start at 0.
cat(list)Concatenates list into a single string, where list is a comma
separated sequence of strings, numbers, points or sets. Numbers are formatted
using at most 6 digits, with no trailing zeros or decimal point (i.e. the
%g format for printf in C). Points are converted to their Cartesian
coordinates. With eukleides abscissa and ordinate are simply separated
by a white space. With euktopst coordinates are formated in the usual
mathematical way, using parenthesis and comma.