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Below is a formal grammar of the pascal language in EBNF notation. It is not 100% complete, some parts such as assembler or objective-c have not been specified.
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![⟨module⟩ = ⟨programmodule ⟩ | ⟨librarymodule⟩ | ⟨packagemodule⟩ | ⟨unitmodule⟩ ;
⟨programmodule⟩ = ⟨programheader⟩ ”;” [ ⟨fullusesclause⟩ ] ⟨block ⟩ ”.” ;
⟨programheader⟩ = ”program ” ⟨identifier⟩ [ ”(” ⟨programparameters⟩ ”)” ] ;
⟨programparameters⟩ = ⟨identifierlist⟩ ;
⟨fullusesclause⟩ = ”uses” ⟨fullusesitem ⟩ ”,” ⟨fullusesitem⟩ ”;” ;
⟨fullusesitem⟩ = ⟨identifier⟩ [ ”in” ⟨stringliteral⟩ ] ;
⟨librarymodule⟩ = ⟨libraryheader⟩ ”;” [ ⟨usesclause⟩ ] ⟨block⟩ ”.” ;
⟨libraryheader⟩ = ”library” ⟨identifier⟩ ;
⟨packagemodule⟩ = ⟨packageheader⟩ ”;” [ ⟨containsclause⟩ ] [⟨requiresclause⟩] ”end ” ”.” ;
⟨packageheader⟩ = ”package ” ⟨identifier⟩ ;
⟨containsclause⟩ = ”contains” ⟨fullusesitem ⟩ ”,” ⟨fullusesitem ⟩ ”;” ;
⟨requiresclause⟩ = ”requires” ⟨qualifierlist⟩ ”;” ;
⟨unitmodule⟩ = ⟨unitheader⟩⟨interfacesection⟩⟨implementationsection⟩([⟨initializationsection⟩
] [ ⟨finalizationsection ⟩ ]
| ”begin” ⟨statementlist⟩ ) ”end” ”.” ;
⟨unitheader⟩ = ”unit” ⟨qualifier⟩ [ ⟨hintdirectives⟩ ] ”;” ;
⟨interfacesection ⟩ = ”interface” [ ⟨usesclause⟩ ] [⟨interfaceparts⟩ ] ;
⟨usesclause⟩ = ”uses” ⟨identifier⟩ ”,” ⟨identifier⟩ ”;” ;
⟨interfaceparts⟩ = ⟨interfacepart⟩ ⟨interfacepart⟩ ;
⟨interfacepart⟩ = ⟨constantdeclarationblock⟩
| ⟨typedeclarationblock⟩
| ⟨variabledeclarationblock⟩
| ⟨propertydeclarationblock⟩
| ⟨procedureheadersblock⟩ ;
⟨implementationsection⟩ = ”implementation ” [ ⟨usesclause⟩ ] ⟨declarationpart⟩ ;
⟨initializationsection⟩ = ”initialization” ⟨statementlist⟩ ;
⟨finalizationsection ⟩ = ” finalization” ⟨statementlist⟩ ;
⟨exportsclause ⟩ = ”exports ” ⟨exportslist⟩ ”;” ;
⟨exportslist⟩ = ⟨exportsentry⟩ ”,” ⟨exportsentry⟩ ;
⟨exportsentry⟩ = ⟨identifier⟩ [ ”index ” ⟨integerconstant⟩ ] [ ”name ” ⟨stringconstant⟩ ] ;
⟨procedureheadersblock ⟩ = ⟨procedureheader⟩
| ⟨functionheader⟩
| ⟨operatorheader⟩;
⟨procedureheader⟩ = ⟨genericprocedureheader⟩
| ⟨regularprocedureheader⟩ ;
⟨genericprocedureheader⟩ = ”generic””procedure ”⟨qualifier⟩⟨generictemplatelist⟩⟨formalparameterlist⟩
”;” [ ⟨callmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨regularprocedureheader⟩ = ”procedure ” ⟨qualifier⟩[⟨generictemplatelist⟩]⟨formalparameterlist⟩
”;” [ ⟨callmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨functionheader⟩ = ⟨genericfunctionheader⟩
| ⟨regularfunctionheader⟩ ;
⟨genericfunctionheader⟩ = ”generic” ”function ” ⟨qualifier⟩ [ ”¡” ⟨generictemplatelist⟩
”¿” ] ⟨formalparameterlist⟩ ”:” ⟨type⟩ [ ⟨callmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨regularfunctionheader⟩ = ”function” ⟨qualifier⟩[”¡”⟨generictemplatelist⟩ ”¿”]⟨formalparameterlist⟩
”:” ⟨type⟩ [ ⟨callmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨operatorheader⟩ = ”operator” ⟨operatordefinition⟩ [ ⟨resultidentifier⟩ ] ”:” ⟨type⟩ ;
⟨operatordefinition⟩ = ⟨assignmentoperatordefinition⟩
| ⟨arithmeticoperatordefinition ⟩
| ⟨comparisonoperatordefinition⟩
| ⟨logicaloperatordefinition⟩
| ⟨otheroperatordefinition⟩ ;
⟨generictemplatelist⟩ = ⟨constrainedtemplatelist⟩
| ⟨freetemplatelist⟩ ;
⟨constrainedtemplatelist⟩ = ⟨constrainedtemplates⟩ ”;” ⟨constrainedtemplates⟩ ;
⟨freetemplatelist⟩ = ⟨identifier⟩ ”,” ⟨qualifier⟩ ;
⟨constrainedtemplates⟩ = ⟨identifierlist⟩ ”:” ⟨typeconstraint⟩ ”,” ⟨typeconstraint⟩ ;
⟨identifierlist⟩ = ⟨identifier⟩ ”,” ⟨identifier⟩ ;
⟨typeconstraint⟩ = ⟨identifier⟩
| ”class”
| ”record” ;
⟨block⟩ = ⟨declarationblock⟩ ⟨statementblock⟩ ;
⟨declarationblock⟩ = ⟨labeldeclarationblock⟩
| ⟨constantdeclarationblock⟩
| ⟨resourcestringdeclarationblock⟩
| ⟨classfuncprocdeclarationblock⟩
| ⟨funcprocdeclarationblock ⟩
| ⟨typedeclarationblock⟩
| ⟨variabledeclarationblock⟩
| ⟨threadvariabledeclarationblock⟩
| ⟨exportsclause⟩ ;
⟨funcprocdeclarationblock⟩ = ⟨proceduredeclaration⟩
| ⟨functiondeclaration⟩
| ⟨constructordeclaration⟩
| ⟨destructordeclaration⟩
| ⟨operatordeclaration⟩ ;
⟨statementblock⟩ = ⟨compoundstatement ⟩ ;
⟨labeldeclarationblock⟩ = ”label” ⟨labeldef⟩ [ ”,” ⟨labeldef⟩ ] ”;” ;](ref253x.png)