%let a=%bquote(' ");
%let b=%nrbquote(' ");
%let c=%nrquote(%' %");
%let d=%nrstr(%' %");
%let e=%quote(%' %");
%let f=%str(%' %");
%let char1 = %bquote(%substr(&infile,1,1));

----------------------------------------------------

[
    ["macro-keyword", "%let"],
    " a",
    ["operator", "="],
    ["macro-string-functions", [
        ["function", "%bquote"],
        ["punctuation", "("],
        "' \"",
        ["punctuation", ")"]
    ]],
    ["punctuation", ";"],
    ["macro-keyword", "%let"],
    " b",
    ["operator", "="],
    ["macro-string-functions", [
        ["function", "%nrbquote"],
        ["punctuation", "("],
        "' \"",
        ["punctuation", ")"]
    ]],
    ["punctuation", ";"],
    ["macro-keyword", "%let"],
    " c",
    ["operator", "="],
    ["macro-string-functions", [
        ["function", "%nrquote"],
        ["punctuation", "("],
        ["escaped-char", "%'"],
        ["escaped-char", "%\""],
        ["punctuation", ")"]
    ]],
    ["punctuation", ";"],
    ["macro-keyword", "%let"],
    " d",
    ["operator", "="],
    ["macro-string-functions", [
        ["function", "%nrstr"],
        ["punctuation", "("],
        ["escaped-char", "%'"],
        ["escaped-char", "%\""],
        ["punctuation", ")"]
    ]],
    ["punctuation", ";"],
    ["macro-keyword", "%let"],
    " e",
    ["operator", "="],
    ["macro-string-functions", [
        ["function", "%quote"],
        ["punctuation", "("],
        ["escaped-char", "%'"],
        ["escaped-char", "%\""],
        ["punctuation", ")"]
    ]],
    ["punctuation", ";"],
    ["macro-keyword", "%let"],
    " f",
    ["operator", "="],
    ["macro-string-functions", [
        ["function", "%str"],
        ["punctuation", "("],
        ["escaped-char", "%'"],
        ["escaped-char", "%\""],
        ["punctuation", ")"]
    ]],
    ["punctuation", ";"],
	["macro-keyword", "%let"],
    " char1 ",
    ["operator", "="],
    ["function", "%bquote"],
    ["punctuation", "("],
    ["macro-keyword", "%substr"],
    ["punctuation", "("],
    ["macro-variable", "&infile"],
    ["punctuation", ","],
    ["number", "1"],
    ["punctuation", ","],
    ["number", "1"],
    ["punctuation", ")"],
    ["punctuation", ")"],
    ["punctuation", ";"]
]

----------------------------------------------------

Checks for all macro string functions.
