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Annotation of researchv10no/cmd/awk/NEW, revision 1.1

1.1     ! root        1: NEW Oct 87:
        !             2: 
        !             3:        New functions toupper(s) and tolower(s) that return
        !             4:        the case-converted version of s.
        !             5: 
        !             6: NEW Jul 87:
        !             7: 
        !             8:        Array sizes are dynamic: hash table grows as elements are added.
        !             9: 
        !            10:        Dynamic regular expressions are cached, up to some limit.
        !            11: 
        !            12: NEW Jun 87:
        !            13: 
        !            14:        Fixed split() so that does split(s,t,/r/) properly;
        !            15:        fixed index(s,/r/) to be an error), since it's wrong.
        !            16: 
        !            17:        String value of a numeric constant is the input representation.
        !            18: 
        !            19: NEW Sept 86:
        !            20: 
        !            21:        Changed order of evaluation of x = y to do rhs first
        !            22: 
        !            23:        New array SYMTAB, the symbol table.
        !            24:        not documented, local pleading only
        !            25: 
        !            26:        -S and -R are officially deprecated;  they can't work
        !            27: 
        !            28: NEW June 86:
        !            29: 
        !            30:        if ((i,j,k) in array) ... now works.
        !            31: 
        !            32: NEW Apr 86:
        !            33: 
        !            34:        Pattern action statements can occur on a single line
        !            35:        if separated by semicolons.
        !            36: 
        !            37:        Grammar revised to eliminate many ambiguities caused
        !            38:        by abuse of > sign.  As a result, constructs like
        !            39:                print a > b c
        !            40:        are syntactically illegal; parens are required.
        !            41: 
        !            42: NEW Jan 86:
        !            43: 
        !            44:        new function  match(s, re)  returns position
        !            45:        in s where re occurs (origin 1) or 0 if not.
        !            46:        new variables RSTART set to pos and RLENGTH
        !            47:        to length of matched string.
        !            48: 
        !            49: NEW Dec 85:
        !            50: 
        !            51:        fixed comment handling so can have
        !            52:                ...,    # comment
        !            53: 
        !            54:        added ?: operator
        !            55: 
        !            56:        added do-while as in C
        !            57: 
        !            58:        arr[i,j], etc., works.  Components separated by SUBSEP,
        !            59:        initialized to \034.
        !            60: 
        !            61: WISH LIST:
        !            62: 
        !            63:        save compiled state
        !            64:        lazy field evaluation
        !            65:        type decls
        !            66:        scanf
        !            67:        access to run-time fcns
        !            68:        c output, link to c
        !            69:        char fcns, left side fcns (e.g., lsubstr)
        !            70:        begin & end in patterns
        !            71:        limits on arrays, etc., ought to be dynamic instead of static.
        !            72: 
        !            73: 
        !            74: CHANGES SO FAR (Jul 85):
        !            75: 
        !            76: added & in replacement of sub() and gsub();  use \& to quote it
        !            77: 
        !            78: mutiple BEGIN's and END's concatenated
        !            79: 
        !            80: replaced error reporting mechanism
        !            81: 
        !            82: "function" is a synonym for "func"
        !            83: 
        !            84: "delete array[elem]" removes elem from array
        !            85: 
        !            86: Fixed bug in field handling for ~ 25% speed up.
        !            87: 
        !            88: Augmented the getline function:
        !            89:        getline
        !            90:                sets $0, NR, NF, $1..., from next input record
        !            91:        getline x
        !            92:                sets x from next input record, sets NR,
        !            93:                but NOT $0, NF, etc.
        !            94:        getline < "foo"
        !            95:                sets $0 from file foo.  sets NF, $1...,
        !            96:                but NOT NR
        !            97:        getline x < "foo"
        !            98:                sets x from foo.  no effect on $0, NF, NR, etc.
        !            99: 
        !           100:        Files are as for print; they are matched by name,
        !           101:        and remain open until explicitly closed.
        !           102:        Input pipes work;  syntax is
        !           103:                "whatever" | getline
        !           104:                "something" | getline x
        !           105:        (This adds a reduce/reduce conflict
        !           106:        to the grammar, so it may be a bad idea.)
        !           107: 
        !           108:        getline returns 0 on EOF, -1 on error, >0 normally
        !           109: 
        !           110: Added close function:
        !           111:        close("foo") calls fclose for right file or pclose for pipe
        !           112: 
        !           113: Added sub(regexp, replacement, str) and gsub(...).
        !           114:        Substitutes replacement for leftmost occurrence
        !           115:        of regexpr in str, or in $0 if no str supplied.
        !           116:        Gsub substitutes for all.  Number of changes
        !           117:        is returned.
        !           118: 
        !           119: Regular expressions can be dynamic.  Any constant string
        !           120:        or variable can be used as a regular expression
        !           121:        in sub(), gsub, or after ~ and !~.
        !           122: 
        !           123: Field separators can be regular expressions, both in FS
        !           124:        and as the 3rd argument of split().
        !           125: 
        !           126: Added "i in arr" condition, for if (...) and patterns.
        !           127:        i in arr  is true if arr[i] has been defined.
        !           128:        Note that this is different from asking if
        !           129:        arr[n] == i for some i!  We are searching for
        !           130:        a subscript, not a value.
        !           131: 
        !           132: terminal i/o, eg stderr
        !           133:        at least for output, no change needed:
        !           134:        print | "cat -u 1>&2"
        !           135:        can only have one of these active at one time.
        !           136: 
        !           137: ARGC and ARGV[] exist, essentially as in C.
        !           138:        ARGC is the number of arguments including the program name.
        !           139:        ARGV[0]..ARGV[ARGC-1] are the arguments
        !           140:        These can be modified in any way at any time.
        !           141:        If an ARGV[i] for i>0 is not null, it is assumed to be
        !           142:        the name of a file and is opened in the normal sequence.
        !           143:        New members of ARGV can be added dynamically beyond the
        !           144:        ones currently processed.
        !           145:        The argument '-' is added when input is stdin.
        !           146: 
        !           147: 
        !           148: added system(), rand(), srand(), sin, cos, atan2
        !           149: 
        !           150: added variable FNR -- line number in current file
        !           151:        can test FNR == 1 to see if in new file
        !           152: 
        !           153: Fixed so that \f, \b, \r, \ddd work in strings as in C
        !           154: 
        !           155: Functions are in:
        !           156:        recursive
        !           157:        arguments are call by value for scalars, by ref for arrays
        !           158:        declaration is
        !           159:                func f(arg list) statement
        !           160:                        arguments by name
        !           161:        arguments are local;  all others global
        !           162:        return [expr]
        !           163: 
        !           164: Order rules relaxed:
        !           165:        BEGIN, END, func declarations can occur anywhere a pattern can.
        !           166: 
        !           167: Added check when syntax error encountered,
        !           168:        for better identification of some errors.
        !           169:        Other error messages better.  Line number in source
        !           170:        and input line line both given for dynamic errors.
        !           171:        Some previously uncaught things now flagged
        !           172:        e.g.    print <= "foo"
        !           173:                print > foo (where foo is null)
        !           174:        detects calls of undefined functions, like foo(bar)

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