by Victor Vella
ETACâ„¢ (pronounced: E-tack) is a general purpose dictionary and stack based interpreted script programming language fully capable of traditional high-level block structured language style syntax.

The ETAC programming language is, arguably, the first of an evolutionary step of dictionary and stack based token activated programming languages, capable of full traditional high-level block structured syntax with the versatility and efficiency of a token activated stack-based language. A token activated programming language operates by sequentially activating text tokens, but not necessarily in one direction only. ETAC is a token activated language that uses 'sequential reverse-flow activation' which activates programmer-determined groups of tokens sequentially from left to right, but the tokens in each group are activated from right to left ('reverse-flow'). This allows the programming language to be written in groups using prefix notation as the programmer desires. It also allows the designer of the programming language to implement high-level block structured syntax, as is usual for traditional programming languages.

[* Function Definitions *]
[* Determines if a sub-string exists in a string sequence. *]
FindString :- fnt:(pStrSeq[*str-seq*] pStr[*str*]) [* => bool *]
RtnVal :- false; [*rtn*]
SrcStr :- ?;

   do with SrcStr of pStrSeq while not RtnVal
      RtnVal := (pop swap find_str pStr SrcStr != -1);

   RtnVal; [*RETURN*]

[* Splits a string sequence at a line number and character offset. *]
SplitLines :- fnt:(pTextLines[*str-seq*] pLineNum[*int*] pCharOff[*int*])
ExtrLine :- ?;

   ExtrLine := pTextLines%[pLineNum] := extr_str 0 pCharOff pTextLines%[pLineNum];

   if (|pTextLines| = pLineNum) then
      {pTextLines +:= ExtrLine;}
      {pTextLines<%[(pLineNum + 1)] := ExtrLine;}

[* Function Calls *]
TextLines :- ["A string here", "Another one", "The final string"];
Found := FindString(TextLines "one");
SplitLines(TextLines 2 7);
Information updated 07/18/20
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