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| ☜ | Scanning Algortitm (Pascal-like)1977 Version of ANSI Standard | ☞ | ||||
TYPE alpha = ARRAY[1..16] OF char;
VAR linact, comact : Boolean; case : char;
FUNCTION traversediagram(diagramname : alpha) : integer;
TYPE exitnode = (X,Y,Z,W);
VAR oneprimitivetraversed, continuescanning, pathtaken, pathexists : Boolean;
exittype : integer;
BEGIN
| oneprimitivetraversed := FALSE;
| continuescanning := TRUE;
| WHILE continuescanning DO
| BEGIN
| | pathtaken := FALSE;
| | pathexists := TRUE;
| | WHILE pathexists DO
| | | BEGIN
| | | | find next path from this syntax node with a primitive symbol on it;
| | | | IF such a path found THEN
| | | | | BEGIN
| | | | | | IF character on the path = character in the window THEN
| | | | | | BEGIN
| | | | | | | exittype := 1;
| | | | | | | oneprimitivetraversed TRUE;
| | | | | | | mark this path as the chosen path to be taken;
| | | | | | | move window one position to the right;
| | | | | | | IF input string is exhausted THEN syntax_ error
| | | | | | | ELSE BEGIN pathtaken := TRUE; pathexists FALSE; END
| | | | | | END
| | | | | END
| | | | ELSE pathexists := FALSE;
| | | END;
| | IF ¬ pathtaken THEN
| | | BEGIN
| | | | pathexists := TRUE;
| | | | WHILE pathexists DO
| | | | BEGIN
| | | | | find next path from this syntax node with a call to "diagramname";
| | | | | IF such a path found THEN
| | | | | | BEGIN
| | | | | | | exittype := traversediagram("diagramname");
| | | | | | | IF exittype ≠ 0 THEN
| | | | | | | BEGIN
| | | | | | | | pathtaken := TRUE;
| | | | | | | | pathexists := FALSE;
| | | | | | | | mark this path as the chosen path to be taken;
| | | | | | | END
| | | | | | END
| | | | | ELSE pathexists := FALSE;
| | | | END
| | | END;
| | IF ¬ (pathtaken) ∧ there is a blank path from this syntax node THEN
| | | BEGIN
| | | | exittype := 1;
| | | | pathtaken := TRUE;
| | | | mark this path as the chosen path to be taken;
| | | END;
| | IF pathtaken THEN
| | | BEGIN
| | | | CASE exittype OF
| | | | | 1: case := 'X';
| | | | | 2: case := 'Y';
| | | | | 3: case := 'Z';
| | | | | 4: case := 'W';
| | | | END;
| | | | find marked path from this syntax node and move to next syntax node along it;
| | | | IF path traversed specified an action THEN
| | | | | BEGIN
| | | | | | IF (linact ∧ comact) ∨ action is a privileged action THEN DO action;
| | | | | END;
| | | | IF next syntax node is an exitnode THEN
| | | | BEGIN
| | | | | continuescanning := FALSE;
| | | | | CASE exitnode OF
| | | | | | Z: traversediagram := 1;
| | | | | | Y: traversediagram := 2;
| | | | | | Z: traversediagram := 3;
| | | | | | W: traversediagram := 4;
| | | | | END
| | | | END
| | | END
| | ELSE
| | BEGIN
| | | IF oneprimitivetraversed THEN syntax error
| | | ELSE
| | | BEGIN
| | | | traversediagram := 0;
| | | | continuescanning := FALSE;
| | | END
| | END
| END
END
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Copyright © Standard Documents; 1977-2024 MUMPS Development Committee;
Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.
This page most recently updated on 15-Nov-2023, 18:58:34.
For comments, contact Ed de Moel (demoel@jacquardsystems.com)