Sethworks Mooseum Annex Exhibit: EGS Standard - Context Specifications


CONTEXT SPECIFICATIONS

The level of an individual statement is indicated by the degree of indentation of that statement from the left.  Two spaces of indentation indicate one level.  Each EGS line begins an even number of spaces from the left margin or begins exactly on the left margin where the "level" of that statement is zero or "root".  Where the statement line wraps around the right side, the remainder is indented to the same degree as the dash.  Odd numbers of spaces before a statement are not used.  [the use of a ASCII editor that does "smart indentation" is highly recommended].

What follows is a specification of the four possible relationships between statements and possible modifications of these relationships:.

Current Statement to statements after.
Statements that occur after the current one occur in the context of the current statement in the same way as conventional english.  This condition applies as a default to all statements in this relationship _except_ where the current statement is type coded with either the "^" or "W" codes.  If either of these codes are used any and all of the following statements are read as if the current statement did not occur.

In all cases the current statement never occurs in the context of statements that follow after.  The current statement provides context and condition on following statements but is not within the context or under the conditions of following statements. the current statement is independant of all statements that follow and is not within the context of them.

Ocassionally the current statement will use the ";" semicolon terminator.  This code indicates that the condition or statement is part of a chain and will be continued in the following "after" statement at the same level.  This terminator is used only to join single statements at the same level.

Example of the use of the down multiple or "W" type code;
      -[0] as a description of lighting codes.
        -[1] where you see that the light is red.
        -[2] W; Where you see the light is green.
          -[a] that the situation is good.
        -[b] that the situation is grim.

In the example the [b] statement occurs in the context of the the [1] modifier and not the [2] and [1] modifiers combined as would be the default interpretation.  The type coding on the [2] modifier applies only to its children or the [a] statement.  Note that all statements occur in the context of the [0] statement.
Current statement to statements below.
Statements that occur below the current one occur in the context of the current statement also.  The context of the current statement applies to all statements in this relationship _especially_ where the current statement is type coded with the "W" code.  The use of this code limits the influence of the scope of current statements context to its branch only.  One main difference between before after context and up down context is that up down context applies equally to each child statement, where before after context varies with distance.

The current statement _is_ affcected by its children statements where they are type coded "^".  Children statements coded in this manner provide "condition" or meaning modification and refinement to the current statement.  The current statement affects all lower statements that are within its branch, except statements that are "^" coded, where the direction of the context is reversed with respect to normal direction of the levels.

Ocassionally the current statement will use the ":" colon terminator.  This code indicates that the condition or statement is part of a chain and will be continued in the following "lower" statements at the next lower level.  This terminator is used only to join a single statements to any one of its clild statements.  Were this terminator is used all of the child statements are continuations of the current statement.  Note that the use of the ":" colon terminator presupposes that none of the children statements will be using the "^" type code.

Example of the colon terminator and the up pointer type code;
      - Jane went:.
        - to Daves house.
        - very quickly.
          - ^; where she was in a hurry.

Current statement to statements before.
The current statement occurs within the context of all statements before it except where those statements are "^" or "W" coded.  The current statement is, at least, partially dependant on "before" statements on the same level.  the relationship between statements before and the current one is similar to the same relationship in conventional english.

Ocassionally the current statement will use the "%" type code. This code indicates that the current statement is a continuation phrase of an earler statement at the same level.  This type code is used where the the "before" statement used a ":" colon terminator code and the child statements have "|" terminator codes.  This form is used for "expanded vector" notation where each of the vector parts requires some sort of conditional modification.
Example of an "expanded vector";
      -1) that jane:.
        -1) writes great novels|.
          - E; the "the New Story".
        -2) can speak eloquently|.
          - E; her speach last saturday.
        -3) is a good listener.
      -2) %; when she {wants to/ puts her mind to it}.

Note that in the example that the first line used a ":" termintor to indicte that the child statements are continuations of the first phrase.  The the "|" terminators on two of the child statements indicate that they will be be continued on the statement following its parent.  The other child statement is not continued where it does not use the "|" bar terminator.  Also the last line contains a "%" precent type code to indicate that it is a continuation clause of the previous branches children.  The "%" code can only be used where there is at least one instance of a "|" terminator.  Finally, the last line contains a defining instance of a vector of two terms.  See the section on "Bracketing Terms" below for details on vector construction.
Current statement to statements above.
The current statement occurs within the context of all statements Above it.  The current statement is completely dependant on "above" statements for context.  Usually the children statements are designed to expand or support the meaning of the above statement.

Where the current statement is "^" coded it redefines or limits the applicability of the parent statement and applies specifically to it.  This is the only time that the current statement defines the context of its immediate parent.

The current statement is a continuation of the parent statement above when that statement ends with a ":" terminator code.


From here, you can:

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Move to the next part on Referencing Statements

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