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General Information

 o Eli: Translator Construction Made Easy
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 o Typical Eli Usage Errors

Tutorials

 o Quick Reference Card
 o Guide For new Eli Users
 o Release Notes of Eli
 o Tutorial on Name Analysis
 o Tutorial on Type Analysis
 o Typical Eli Usage Errors

Reference Manuals

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 o LIDO Reference Manual
 o Typical Eli Usage Errors

Libraries

 o Eli library routines
 o Specification Module Library

Translation Tasks

 o Lexical analysis specification
 o Syntactic Analysis Manual
 o Computation in Trees

Tools

 o LIGA Control Language
 o Debugging Information for LIDO
 o Graphical ORder TOol

 o FunnelWeb User's Manual

 o Pattern-based Text Generator
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 o Generating Unparsing Code

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Tutorial on Name Analysis

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Messages on Scope Rule Violations

Erroneous programs may violate the scope rules in one of two cases:

  • A particular applied identifier occurrence has no valid defining identifier occurrence.

  • An identifier in a range may have more one defining occurrences.

Such situations shall be indicated by error messages. Furthermore, we want every defining occurrence of a multiply defined identifier to be marked by a message.

For that purpose we use the following two library modules:

CoreChk.specs[9]==

$/Tech/Strings.specs
$/Prop/OccCnt.gnrc:inst
This macro is attached to a product file.

The Strings module provides a function that concatenates an error message string and an identifier for error messages related to identifiers, see String Concatenation of Specification Module Library: Common Problems.

The OccCnt module provides computations that count how often an object identified by a Key attribute occurs in a certain context, in our case in a defining context. See Count Occurrences of Objects of Specification Module Library: Properties of Definitions, for more information.

The check for existence of a definition is directly obtained from the module role ChkIdUse. For the second check we specify a computational role ChkUnique in order to reuse it for several grammar symbols. If an object occurs more than once in the ChkUnique context it is multiply defined.

CoreChk.lido[10]==

SYMBOL ChkUnique INHERITS Count, TotalCnt COMPUTE
  IF (GT (THIS.TotalCnt, 1),
  message (ERROR, CatStrInd ("identifier is multiply defined: ", 
                             THIS.Sym),
           0, COORDREF));
END;

SYMBOL UseIdent INHERITS ChkIdUse END;
SYMBOL DefIdent INHERITS ChkUnique END;
This macro is attached to a product file.


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