code inside section

code.tex

\makeatletter
\def\code{%
	\@ifnextchar{|}%
		{\code@sect}%
		{\code@inline}%
}

\def\code@inline#1{%
	\lstinline[style=ocaml, basicstyle=\small\tt, keywordstyle=\small\sl, columns={fullflexible,keepspaces}, mathescape]|#1| }

\def\code@sect|#1|{%
	\lstinline[style=ocaml, basicstyle=\tt, keywordstyle=\sl, columns={fullflexible,keepspaces}, mathescape]|#1| }
\makeatother

\code{if e1 then e2 else e3}
\code|if e1 then e2 else e3|