NAME

stringinttab − string table lookup module

SYNOPSIS

include "strinttab.m";
StringInt: import StringIntTab;
 strinttab := load StringIntTab StringIntTab->PATH;
 StringInt: adt{
    key: string;
    val: int;
};
 lookup:    fn(tab: array of StringInt, key: string) : (int, int);
revlookup: fn(tab: array of StringInt, val: int)    : string;

DESCRIPTION

­Stringinttab provides functions that perform forward and reverse searches of an ordered table of ­key−value pairs. 

A table should be constructed as an array of ­StringInt entries, ordered by increasing ­key value.  Keys ordering is determined by comparison of the Unicode value of their characters. 

­Lookup performs a binary search of ­tab for the ­StringInt entry whose ­key field has a value equal to ­key and returns a tuple: an ­int whose value is non-zero if a match has been found and zero otherwise, and an ­int whose value is equal to the ­val field of the matching ­StringInt entry. 

­Revlookup searches ­tab for the first ­StringInt entry whose ­val field has a value equal to ­val and returns the corresponding ­key string. 

EXAMPLES

T := load StringIntTab StringIntTab->PATH;
 fmtstringtab := array[] of { Strinttab->StringInt
("html", FHtml),
("latex", FLatex),
("latexbook", FLatexBook),
("latexpart", FLatexPart),
("latexproc", FLatexProc),
("latexslides", FLatexSlides),
};
 (fnd, fmt) := T->lookup(fmtstringtab, "latexbook");
fmtstring := T->revlookup(fmtstringtab, FLatex);

SOURCE

­/appl/lib/strinttab.b

SEE ALSO

hash(2)

BUGS

­Revlookup performs a sequential search of the table. 
 

Plan 9  —  June 29, 2000