Format/typo check 1993/vanb + add alt code

The alt code was provided by the author as a kind of spoiler but I fixed
it to also work with clang like I did with the original entry.

Silenced some warnings (all on macOS are now silenced, at least with
default cc which is clang).

Format/typo check README.md file.

This should complete 1993/vanb.

1993/vanb/.gitignore

@@ -1,3 +1,4 @@
 vanb
+vanb.alt
 vanb.orig
 prog.orig

1993/vanb/Makefile

@@ -38,7 +38,8 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-deprecated-non-prototype -Wno-unused-value
+CSILENCE= -Wno-deprecated-non-prototype -Wno-unused-value -Wno-unused-parameter \
+	  -Wno-implicit-int
 
 # Common C compiler warning flags
 #
@@ -112,8 +113,8 @@ OBJ= ${PROG}.o
 DATA=
 TARGET= ${PROG}
 #
-ALT_OBJ=
-ALT_TARGET=
+ALT_OBJ= ${PROG}.alt.o
+ALT_TARGET= ${PROG}.alt
 
 
 #################

1993/vanb/README.md

@@ -4,6 +4,16 @@
 make all
 ```
 
+### Bugs and (Mis)features:
+
+The current status of this entry is:
+
+```
+STATUS: INABIAF - please **DO NOT** fix
+```
+
+For more detailed information see [1993 vanb in bugs.md](/bugs.md#1993-vanb).
+
 
 ## To use:
 
@@ -33,8 +43,8 @@ The octal expression may contain:
 ```
 unary operators:	+, -
 binary operators	+, -, *, /, %
-hex numbers:		x or X follow by hex digits
-decimal numbers:	d or D follow by decimal digits
+hex numbers:		x or X followed by hex digits
+decimal numbers:	d or D followed by decimal digits
 octal numbers:		octal digits
 grouping:		()
 ```
@@ -57,12 +67,12 @@ decimal `-46` would be entered as `-d46` and not `d-46`.
 0. Of course, the fact that the program takes input and produces output in
 octal, rather than a more useful system like decimal, makes it "special".
 
-1. The entire program consists of a single expression, returned from main.
+1. The entire program consists of a single expression, returned from `main()`.
 
-2. There are no global or local variables other than the parameters to main.
+2. There are no global or local variables other than the parameters to `main()`.
 
 3. All of the constants in the program are expressed in octal - including the
-printf string.
+`printf(3)` string.
 
 4. The variables are given names which cause visual confusion with the octal
 constants.
@@ -77,8 +87,8 @@ time, to make the program harder to understand.
 
 ### How It Works:
 
-It's a recursive descent parser, calling `main`
-for all of its recursion. `O2` is a state variable, telling main
+It's a recursive descent parser, calling `main()`
+for all of its recursion. `O2` is a state variable, telling `main()`
 what grammar non-terminal to parse. `**O7` is the next character.
 `O3` is an intermediate result. Whenever you see a construct like:
 
@@ -86,10 +96,10 @@ what grammar non-terminal to parse. `**O7` is the next character.
 !(expression with O2)?
 ```
 
-it's decrementing & testing `O2` to see what state it's in. Comparisons
+it's decrementing and testing `O2` to see what state it's in. Comparisons
 involving `**O7` and octal constants are looking for certain characters.
 
-Here's the grammar `('e'` denotes the empty string) :
+Here's the grammar (`'e'` denotes the empty string) :
 
 
 ```
@@ -103,7 +113,7 @@ Here's the grammar `('e'` denotes the empty string) :
 <X>  ::=  [0-9]<X> | [A-F]<X> | [a-f]<X> | e
 <O>  ::=  [0-7]<O> | e
 ```
-\
+
 Here's how the grammar nonterminals map to octal state numbers:
 
 ```

1993/vanb/vanb.alt.c

@@ -0,0 +1,35 @@
+O5(O2,O7,O3)char**O7;
+{
+	 return
+/* N1 */ !(O2+=~01+01) ?\
+	      00:
+/* N2 */ !(O2-=02>01) ?\
+	      printf("\045\157\012",O5(012,O7+01,00)):
+/* O  */ !(O2-=02>>01) ?\
+	      (**O7<=067 && **O7>057 ? O5(03,O7,*(*O7)++-060+010*O3):O3):
+/* D  */ !(O2-=-O3-~O3) ?\
+	      (072>**O7 && 060<=**O7 ? O5(04,O7,012*O3-060+*(*O7)++):O3):
+/* X  */ !(O2-=!O3+!!O3) ?\
+	      (**O7>057 && **O7<=071 ? O5(05,O7,*(*O7)+++O3*020-060):
+	      **O7<=0106 && 0101<=**O7 ? O5(05,O7,020*O3+*(*O7)++-067):
+	      0140<**O7 && **O7<0147 ? O5(05,O7,-0127+*(*O7)+++020*O3):O3):
+/* F  */ !(O2-=02-01) ?\
+	      (**O7==050 ? 050**++*O7,O5(013,O7,O5(012,O7,00)):
+	      **O7<056 && 054<**O7 ? 055**++*O7,-O5(06,O7,00):
+	      054>**O7 && 052<**O7 ? 050**(*O7)++,O5(06,O7,00):
+	      !(**O7^0170)||!(0130^**O7) ? *++*O7,O5(05,O7,00):
+	      **O7==0144||**O7==0104 ? ++*O7,O5(04,O7,00):O5(03,O7,00)):
+/* T' */ !--O2 ?\
+	      (**O7==052 ? O5(07,O7,O3*(*++*O7,O5(06,O7,00))):
+	      !(045-**O7) ? O5(07,O7,O3%(03+(*O7)++,O5(06,O7,00))):
+	      !(**O7^057) ? O5(07,O7,O3/(03-*++*O7,O5(06,O7,00))):O3):
+/* T  */ !(O2+=01-02) ?\
+	      O5(07,O7,O5(06,O7,00)):
+/* E' */ !(O2+=-02/02) ?\
+	      (!(**O7-053)?O5(011,O7,O3+(++*O7,O5(010,O7,00))):
+	      !(055^**O7) ? O5(011,O7,O3-(03+*(*O7)++,O5(010,O7,00))):O3):
+/* E  */ !(O2-=0563&0215) ?\
+	      O5(011,O7,O5(010,O7,00)):
+/* C  */ (++*O7,O3);
+}
+main(O2,O7,O3)char**O7,**O3;{return O5(O2,O7,0);}