\documentclass{article}
\usepackage{agda}

\begin{document}

\begin{code}%
\>[0]\AgdaComment{-- We use non-standard spaces between the name of the term and the}\<%
\\
\>[0]\AgdaComment{-- colon.}\<%
\\
\>[0]\AgdaKeyword{postulate}\<%
\\
\>[0][@{}l@{\AgdaIndent{0}}]%
\>[2]\AgdaPostulate{s00A0}\AgdaSpace{}%
\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPrimitiveType{Set}%
\>[15]\AgdaComment{-- NO-BREAK SPACE        ("\textbackslash{} " with Agda input method)}\<%
\\
%
\>[2]\AgdaPostulate{s2004}\AgdaSpace{}%
\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPrimitiveType{Set}%
\>[15]\AgdaComment{-- THREE-PER-EM SPACE    ("\textbackslash{};" with Agda input method)}\<%
\\
%
\>[2]\AgdaPostulate{s202F}\AgdaSpace{}%
\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPrimitiveType{Set}%
\>[15]\AgdaComment{-- NARROW NO-BREAK SPACE ("\textbackslash{}," with Agda input method)}\<%
\end{code}

% Various whitespace characters: "    ".
\begin{code}%
\>[0]\AgdaKeyword{open}\AgdaSpace{}%
\AgdaKeyword{import}\AgdaSpace{}%
\AgdaModule{Agda.Builtin.String}\<%
\\
%
\\[\AgdaEmptyExtraSkip]%
\>[0]\AgdaComment{-- Various whitespace characters: "    ".}\<%
\\
%
\\[\AgdaEmptyExtraSkip]%
\>[0]\AgdaFunction{various-whitespace-characters}\AgdaSpace{}%
\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPostulate{String}\<%
\\
\>[0]\AgdaFunction{various-whitespace-characters}\AgdaSpace{}%
\AgdaSymbol{=}\AgdaSpace{}%
\AgdaString{"    "}\<%
\end{code}

\end{document}
