\newcommand: Define a new command.
\newenvironment: Define a new environment.
\newtheorem: Define a new theorem-like environment.
\newfont: Define a new font name.
############################################################
\newcommand ::newcommand::renewcommand::
############################################################
\newcommand{cmd}[args]{definition}
\newcommand{cmd}[args][default]{definition}
\renewcommand{cmd}[args]{definition}
\renewcommand{cmd}[args][default]{definition}
These commands define (or redefine) a command.
cmd A command name beginning with a \. For
\newcommand it must not be already defined and
must not begin with \end; for \renewcommand it
must already be defined.
args An integer from 1 to 9 denoting the number of
arguments of the command being defined. The
default is for the command to have no arguments.
def If this optional parameter is present, it means
that the command's first argument is optional.
The default value of the optional argument is def.
definition The text to be substituted for every
occurrence of cmd; a parameter of the form #n in
cmd is replaced by the text of the nth argument
when this substitution takes place.
############################################################
\newenvironment ::newenvironment::renewenvironment::
############################################################
\newenvironment{nam}[args]{begdef}{enddef}
\newenvironment{nam}[args][default]{begdef}{enddef}
\renewenvironment{nam}[args]{begdef}{enddef}
These commands define or redefine an environment.
nam The name of the environment. For \newenvironment
there must be no currently defined environment
by that name, and the command \nam must be
undefined. For \renewenvironment the environment
must already be defined.
args An integer from 1 to 9 denoting the number of
arguments of the newly-defined environment.
The default is no arguments.
default If this is specified, the first argument
is optional, and default gives the default value
for that argument.
begdef The text substituted for every occurrence of
\begin{nam}; a parameter of the form #n in cmd
is replaced by the text of the nth argument when
this substitution takes place.
enddef The text substituted for every occurrence of
\end{nam}. It may not contain any argument
parameters.
############################################################
\newtheorem ::newtheorem::
############################################################
\newtheorem{env_name}{caption}[within]
\newtheorem{env_name}[numbered_like]{caption}
This command defines a theorem-like environment.
env_name The name of the environment to be defined.
A string of letters. It must not be the
name of an existing environment or counter.
caption The text printed at the beginning of the
environment, right before the number.
This may simply say "Theorem", for example.
within The name of an already defined counter,
usually of a sectional unit. Provides a
means of resetting the new theorem counter
within the sectional unit.
numbered_like The name of an already defined theorem-like
environment.
The \newtheorem command may have at most one optional argument.
############################################################
\newfont ::newfont::
############################################################
\newfont{cmd}{font_name}
Defines the command name cmd, which must not be currently
defined, to be a declaration that selects the font named
font_name to be the current font.
