今天捣鼓了一下tex.web。有一点基础的同学可能知道.web文件通过两个命令可以得到两种不同类型，即:
-
tangle tex.web得到 tex.p （pascal程序文件） -
weave tex.web得到 tex.tex （tex文件）
一般情况下，得到的pascal文件会非常怪异，比如：
{4:}{9:}{$C-,A+,D-}{[$C+,D+]}{:9}program TEX;label{6:}1,9998,9999;
{:6}const{11:}memmax=30000;memmin=0;bufsize=500;errorline=72;
halferrorline=42;maxprintline=79;stacksize=200;maxinopen=6;fontmax=75;
fontmemsize=20000;paramsize=60;nestsize=40;maxstrings=3000;
stringvacancies=8000;poolsize=32000;savesize=600;triesize=8000;
trieopsize=500;dvibufsize=800;filenamesize=40;
poolname='TeXformats:TEX.POOL ';
{:11}type{18:}ASCIIcode=0..255;{:18}{25:}eightbits=0..255;
alphafile=packed file of char;bytefile=packed file of eightbits;
{:25}{38:}poolpointer=0..poolsize;strnumber=0..maxstrings;
packedASCIIcode=0..255;{:38}{101:}scaled=integer;
nonnegativeinteger=0..2147483647;smallnumber=0..63;
{:101}{109:}glueratio=real;{:109}{113:}quarterword=0..255;
halfword=0..65535;twochoices=1..2;fourchoices=1..4;
twohalves=packed record rh:halfword;case twochoices of 1:(lh:halfword);
2:(b0:quarterword;b1:quarterword);end;
fourquarters=packed record b0:quarterword;b1:quarterword;b2:quarterword;
b3:quarterword;end;
memoryword=record case fourchoices of 1:(int:integer);2:(gr:glueratio);
3:(hh:twohalves);4:(qqqq:fourquarters);end;wordfile=file of memoryword;
{:113}{150:}glueord=0..3;
这个就是 Plain 的 Pacal 源文件，用free pascal稍微整理一下得到下面的代码：
ptop -i tex.p tex_out.p
得到如下代码：
{4:}{9:}{$C-,A+,D-}{[$C+,D+]}{:9}
Program TEX;
Label {6:}1,9998,9999;
{:6}
Const {11:}memmax = 30000;
memmin = 0;
bufsize = 500;
errorline = 72;
halferrorline = 42;
maxprintline = 79;
stacksize = 200;
maxinopen = 6;
fontmax = 75;
fontmemsize = 20000;
paramsize = 60;
nestsize = 40;
maxstrings = 3000;
stringvacancies = 8000;
poolsize = 32000;
savesize = 600;
triesize = 8000;
trieopsize = 500;
dvibufsize = 800;
filenamesize = 40;
poolname = 'TeXformats:TEX.POOL ';
{:11}
Type {18:}ASCIIcode = 0..255;{:18}{25:}
eightbits = 0..255;
alphafile = packed file Of char;
bytefile = packed file Of eightbits;
{:25}{38:}
poolpointer = 0..poolsize;
strnumber = 0..maxstrings;
packedASCIIcode = 0..255;{:38}{101:}
scaled = integer;
nonnegativeinteger = 0..2147483647;
smallnumber = 0..63;
{:101}{109:}
glueratio = real;{:109}{113:}
quarterword = 0..255;
halfword = 0..65535;
twochoices = 1..2;
fourchoices = 1..4;
twohalves = packed Record
rh: halfword;
Case twochoices Of
1: (lh:halfword);
2: (b0:quarterword;b1:quarterword);
End;
fourquarters = packed Record
b0: quarterword;
b1: quarterword;
b2: quarterword;
b3: quarterword;
End;
memoryword = Record
Case fourchoices Of
1: (int:integer);
2: (gr:glueratio);
3: (hh:twohalves);
4: (qqqq:fourquarters);
End;
wordfile = file Of memoryword;
{:113}{150:}
glueord = 0..3;
代码可读许多。
