\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{}%
\AgdaPrimitive{Set}%
\>[15]\AgdaComment{--\ NO-BREAK\ SPACE\ \ \ \ \ \ \ \ ("\textbackslash{}\ "\ with\ Agda\ input\ method)}\<%
\\
%
\>[2]\AgdaPostulate{s2004}\AgdaSpace{}%
\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPrimitive{Set}%
\>[15]\AgdaComment{--\ THREE-PER-EM\ SPACE\ \ \ \ ("\textbackslash{};"\ with\ Agda\ input\ method)}\<%
\\
%
\>[2]\AgdaPostulate{s202F}\AgdaSpace{}%
\AgdaSymbol{:}\AgdaSpace{}%
\AgdaPrimitive{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}
