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AlloyTools / org.alloytools.alloy

Alloy is a language for describing structures and a tool for exploring them. It has been used in a wide range of applications from finding holes in security mechanisms to designing telephone switching networks. This repository contains the code for the tool.
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Evaluator not recognizing variable name. Error: The name cannot contain the '$' symbol. #235

Closed luomein closed 4 months ago

luomein commented 4 months ago

Alloy 6.1.0, Mac OS 13.6.3

In the Evaluator, sometimes the variable name will raise error, The name cannot contain the '$' symbol.

{Node$0} ---> work fine {Node$1} ---> work fine {Node$0} + {Node$1} ---> work fine {Node$0, Node$1} ---> error1 {(Node$0), (Node$1)} ---> error2 {List$0->Node$0, List$0->Node$1} ---> error2

error1: The name cannot contain the '$' symbol.

error2: Syntax error at line 1 column 10: There are 38 possible tokens that can appear here: ! # ( * @ Int NAME NUMBER STRING String ^ after all always before disj eventually fun historically iden int let lone no none once one pred seq set some steps sum this univ { } ~

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pkriens commented 4 months ago

The '{' is not valid Alloy syntax. Message could be better but the curly braces are the problem. This works:

(Node$0+Node$1) & Node$1

For convenience, you can also use the Foo¹ that you can copy from the output.