From Code to Community: Sponsoring The Perl and Raku Conference 2025 Learn more

BRMILLER / LaTeXML-0.8.6_1 / t / tokenize / equality.tex 

            

              
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131

              
\documentclass{article}
\title{Testing equality vs. catcodes}
\begin{document}
\section{Begin 1}
{
Pretest (not): \ifx{& equals\else not\fi
Mangle...
\catcode`\&=1\relax
BRACE: \the\catcode`\{; \meaning{.
AMP: \the\catcode`\&; \meaning&.
Test (not): \ifx{& equals\else not\fi
}
\section{Math 3}
{
Pretest (not): \ifx$& equals\else not\fi
Mangle...
\catcode`\&=3\relax
DOLLAR: \the\catcode`\$; \meaning$.
AMP: \the\catcode`\&; \meaning&.
Test (not): \ifx$& equals\else not\fi
\let\foo$
Test (equals): \ifx$\foo equals\else not\fi
\let\bar&
Test (not): \ifx$\bar equals\else not\fi
Test (equals): \ifx&\bar equals\else not\fi
But still acts like math:&a&.
}
\section{Math 3 w/let}
{
Pretest (not): \ifx$& equals\else not\fi
Mangle...
\catcode`\&=\active\let&$
DOLLAR: \the\catcode`\$; \meaning$.
AMP: \the\catcode`\&; \meaning&.
Test (equals): \ifx$& equals\else not\fi
But still acts like math:&a&.
}
\section{Math 3 w/let, uncatcode}
{
Pretest (not): \ifx$& equals\else not\fi
Mangle...
\catcode`\&=\active\let&$
\catcode`\&=4\relax
DOLLAR: \the\catcode`\$; \meaning$.
AMP: \the\catcode`\&; \meaning&.
Test (not): \ifx$& equals\else not\fi
But does NOT act like math.
}
\section{Param 6}
{
Pretest (not): \ifx#& equals\else not\fi
Mangle...
\catcode`\&=6\relax
HASH: \the\catcode`\#; \meaning#.
AMP: \the\catcode`\&; \meaning&.
Test (not): \ifx#& equals\else not\fi
}
\section{MathActive}
{
Pretest (not): \ifx'& equals\else not\fi
Mangle...
\makeatletter
\mathcode`\&="8000
{\catcode`\&=\active \global\let&\active@math@prime}
\makeatother
PRIME: \the\catcode`\'; \meaning'.
AMP: \the\catcode`\&; \meaning&.
Test (not): \ifx#& equals\else not\fi
But works as prime?
NO %%% $ a&& $
}
\section{Control Sequences}
% But "defn" is the same
Compare 2 undefined control sequences:
\ifx\stinky\poo equals \else not\fi
Let one to relax:
\let\poo\relax
\ifx\stinky\poo equals \else not\fi
Let both to relax:
\let\poo\relax
\let\stinky\relax
\ifx\stinky\poo equals \else not\fi
\def\foo{FOO}
\let\bar\foo
Test (equals): \ifx\bar\foo equals\else not\fi
\makeatletter
\let\baz\active@math@prime
\makeatother
Test (not): \ifx'\baz equals \else not \fi
Test (not in math): $\ifx'\baz equals \else not \fi$
\end{document}