Archives

Today, in work, we wound up discussing this classic DailyWTF.com article — “Remember, the enterprisocity of an application is directly proportionate to the number of constants defined”:

public class SqlWords
{
  public const string SELECT = " SELECT ";
  public const string TOP = " TOP ";
  public const string DISTINCT = " DISTINCT ";
  /* etc. */
}

public class SqlQueries
{
  public const string SELECT_ACTIVE_PRODCUTS =
    SqlWords.SELECT +
    SqlWords.STAR +
    SqlWords.FROM +
    SqlTables.PRODUCTS +
    SqlWords.WHERE +
    SqlColumns.PRODUCTS_ISACTIVE +
    SqlWords.EQUALS +
    SqlMisc.NUMBERS_ONE;
  /* etc. */
}

This made me recall the legendary source code for the original Bourne shell, in Version 7 Unix. As this article notes:

Steve Bourne, at Bell Labs, worked on his version of shell starting from 1974 and this shell was released in 1978 as Bourne shell. Steve previously was involved with the development of Algol-68 compiler and he transferred general approach and some syntax sugar to his new project.

“Some syntax sugar” is an understatement. Here’s an example, from cmd.c:

LOCAL REGPTR    syncase(esym)
        REG INT esym;
{
        skipnl();
        IF wdval==esym
        THEN    return(0);
        ELSE    REG REGPTR      r=getstak(REGTYPE);
                r->regptr=0;
                LOOP wdarg->argnxt=r->regptr;
                     r->regptr=wdarg;
                     IF wdval ORF ( word()!=')' ANDF wdval!='|' )
                     THEN synbad();
                     FI
                     IF wdval=='|'
                     THEN word();
                     ELSE break;
                     FI
                POOL
                r->regcom=cmd(0,NLFLG|MTFLG);
                IF wdval==ECSYM
                THEN    r->regnxt=syncase(esym);
                ELSE    chksym(esym);
                        r->regnxt=0;
                FI
                return(r);
        FI
}

Here are the #define macros Bourne used to “Algolify” the C compiler, in mac.h:

/*
 *      UNIX shell
 *
 *      S. R. Bourne
 *      Bell Telephone Laboratories
 *
 */

#define LOCAL   static
#define PROC    extern
#define TYPE    typedef
#define STRUCT  TYPE struct
#define UNION   TYPE union
#define REG     register

#define IF      if(
#define THEN    ){
#define ELSE    } else {
#define ELIF    } else if (
#define FI      ;}

#define BEGIN   {
#define END     }
#define SWITCH  switch(
#define IN      ){
#define ENDSW   }
#define FOR     for(
#define WHILE   while(
#define DO      ){
#define OD      ;}
#define REP     do{
#define PER     }while(
#define DONE    );
#define LOOP    for(;;){
#define POOL    }


#define SKIP    ;
#define DIV     /
#define REM     %
#define NEQ     ^
#define ANDF    &&
#define ORF     ||

#define TRUE    (-1)
#define FALSE   0
#define LOBYTE  0377
#define STRIP   0177
#define QUOTE   0200

#define EOF     0
#define NL      '\n'
#define SP      ' '
#define LQ      '`'
#define RQ      '\''
#define MINUS   '-'
#define COLON   ':'

#define MAX(a,b)        ((a)>(b)?(a):(b))

Having said all that, the Bourne shell was an awesome achievement; many of the coding constructs we still use in modern Bash scripts, 30 years later, are identical to the original design.