Definition of a LaTeX for loop

I have turned this code into a package and placed it on CTAN. Rather than copy and paste the code below (which won't be updated), I suggest you download this package and install it.

The following requires the ifthen package.

\newcommand{\forloop}[5][1]%
{%
\setcounter{#2}{#3}%
\ifthenelse{#4}%
	{%
	#5%
	\addtocounter{#2}{#1}%
	\forloop[#1]{#2}{\value{#2}}{#4}{#5}%
	}%
% Else
	{%
	}%
}%

which is used in the following manner


\forloop[step]{counter}{initial_value}{conditional}{code_block}

For example:

\newcounter{ct}
\forloop{ct}{1}{\value{ct} < 5}%
{%
\arabic{ct}
}

This is the old code that is deprecated

\newcommand{\forLoop}[5][1]
{%
\setcounter{#4}{#2}%
\ifthenelse{ \value{#4} < #3 }%
	{%
	#5%
	\addtocounter{#4}{#1}%
	\forLoop[#1]{\value{#4}}{#3}{#4}{#5}%
	}%
% Else
	{%
	\ifthenelse{\value{#4} = #3}%
		{%
		#5%
		}%
	% Else
		{}%
	}%
}

This is invoked by

\newcounter{ct}
\forLoop[step]{start}{end}{ct}{latex_code}

The reason for the need to define a counter is to allow nested for loops; for instance, if you wanted to make an 10 by 10 identity matrix:

\newcounter{identRow}
\newcounter{identCol}
\inp{
	\begin{array}{*{10}{c}}
	\forLoop{1}{10}{identRow}
		{
		\forLoop{1}{10}{identCol}
			{
			\ifthenelse{  \equal{ \value{identRow} }{ \value{identCol} }  }{  1  }{  0  }
			\ifthenelse{  \equal{\value{identCol}}{10} }{}{ & }
			}
		\\
		}
	\end{array}
}