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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⟩ = ⟨programxmodule⟩ | ⟨libraryxmodule⟩ | ⟨packagexmodule⟩ | ⟨unitxmodule⟩ ;
⟨programxmodule⟩ = ⟨programxheader⟩ ”;” [ ⟨fullxusesxclause⟩ ] ⟨block⟩ ”.” ;
⟨programxheader⟩ = ”program ” ⟨identifier⟩ [ ” (” ⟨programxparameters⟩ ”)” ] ;
⟨programxparameters⟩ = ⟨identifierxlist⟩ ;
⟨fullxusesxclause⟩ = ”uses” ⟨fullxusesxitem ⟩ ”,” ⟨fullxusesxitem ⟩ ”;” ;
⟨fullxusesxitem⟩ = ⟨identifier⟩ [ ”in” ⟨stringxliteral⟩ ] ;
⟨libraryxmodule⟩ = ⟨libraryxheader⟩ ”;” [ ⟨usesxclause⟩ ] ⟨block⟩ ”.” ;
⟨libraryxheader⟩ = ”library” ⟨identifier⟩ ;
⟨packagexmodule⟩ = ⟨packagexheader⟩ ”;” [ ⟨containsxclause⟩ ] [⟨requiresxclause⟩] ”end ”
”.” ;
⟨packagexheader⟩ = ”package ” ⟨identifier⟩ ;
⟨containsxclause⟩ = ”contains” ⟨fullxusesxitem⟩ ”,” ⟨fullxusesxitem⟩ ”;” ;
⟨requiresxclause⟩ = ”requires” ⟨qualifierxlist⟩ ”;” ;
⟨unitxmodule⟩ = ⟨unitxheader⟩⟨interfacexsection⟩⟨implementationxsection⟩( [⟨initializationxsection ⟩
] [ ⟨finalizationxsection ⟩ ]
| ”begin” ⟨statementxlist⟩ ) ”end” ”.” ;
⟨unitxheader⟩ = ”unit” ⟨qualifier⟩ [ ⟨hintdirectives⟩ ] ”;” ;
⟨interfacexsection⟩ = ”interface” [ ⟨usesxclause⟩ ] [⟨interfacexparts⟩ ] ;
⟨usesxclause⟩ = ”uses” ⟨identifier⟩ ”,” ⟨identifier⟩ ”;” ;
⟨interfacexparts⟩ = ⟨interfacexpart⟩ ⟨interfacexpart⟩ ;
⟨interfacexpart⟩ = ⟨constantxdeclarationxblock ⟩
| ⟨typexdeclarationxblock⟩
| ⟨variablexdeclarationxblock⟩
| ⟨propertyxdeclarationxblock⟩
| ⟨procedurexheadersxblock⟩ ;
⟨implementationxsection⟩ = ”implementation ” [ ⟨usesxclause⟩ ] ⟨declarationxpart⟩ ;
⟨initializationxsection⟩ = ”initialization ” ⟨statementxlist⟩ ;
⟨finalizationxsection⟩ = ”finalization” ⟨statementxlist⟩ ;
⟨exportsxclause⟩ = ”exports” ⟨exportsxlist⟩ ”;” ;
⟨exportsxlist⟩ = ⟨exportsxentry⟩ ”,” ⟨exportsxentry⟩ ;
⟨exportsxentry⟩ = ⟨identifier⟩ [ ”index ” ⟨integerxconstant⟩ ] [ ”name ” ⟨stringxconstant⟩ ]
;
⟨procedurexheadersxblock⟩ = ⟨procedurexheader⟩
| ⟨functionxheader⟩
| ⟨operatorxheader⟩;
⟨procedurexheader⟩ = ⟨genericxprocedurexheader⟩
| ⟨regularxprocedurexheader⟩ ;
⟨genericxprocedurexheader⟩ = ”generic” ”procedure ” ⟨qualifier⟩ ⟨genericxtemplatexlist⟩
⟨formalxparameterxlist⟩ ”;” [ ⟨callxmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨regularxprocedurexheader⟩ = ”procedure ”⟨qualifier⟩[⟨genericxtemplatexlist⟩]⟨formalxparameterxlist⟩
”;” [ ⟨callxmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨functionxheader⟩ = ⟨genericxfunctionxheader⟩
| ⟨regularxfunctionxheader⟩ ;
⟨genericxfunctionxheader⟩ = ”generic” ”function” ⟨qualifier⟩[”¡” ⟨genericxtemplatexlist⟩
”¿” ] ⟨formalxparameterxlist⟩ ”:” ⟨type⟩ [ ⟨callxmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨regularxfunctionxheader⟩ = ”function” ⟨qualifier⟩ [” ¡” ⟨genericxtemplatexlist⟩”¿” ]⟨formalxparameterxlist⟩
”:” ⟨type⟩ [ ⟨callxmodifiers⟩ ”;” ] [⟨hintdirectives⟩] ;
⟨operatorxheader⟩ = ”operator” ⟨operatorxdefinition⟩ [ ⟨resultxidentifier ⟩ ] ”:” ⟨type⟩ ;
⟨operatorxdefinition⟩ = ⟨assignmentxoperatorxdefinition ⟩
| ⟨arithmeticxoperatorxdefinition⟩
| ⟨comparisonxoperatorxdefinition⟩
| ⟨logicalxoperatorxdefinition⟩
| ⟨otherxoperatorxdefinition⟩ ;
⟨genericxtemplatexlist⟩ = ⟨constrainedxtemplatexlist⟩
| ⟨freextemplatexlist⟩ ;
⟨constrainedxtemplatexlist⟩ = ⟨constrainedxtemplates⟩ ”;” ⟨constrainedxtemplates⟩ ;
⟨freextemplatexlist⟩ = ⟨identifier⟩ ”,” ⟨qualifier⟩ ;
⟨constrainedxtemplates⟩ = ⟨identifierxlist⟩ ”:” ⟨typexconstraint⟩ ”,” ⟨typexconstraint⟩ ;
⟨identifierxlist⟩ = ⟨identifier⟩ ”,” ⟨identifier⟩ ;
⟨typexconstraint⟩ = ⟨identifier⟩
| ”class”
| ”record” ;
⟨block⟩ = ⟨declarationxblock⟩ ⟨statementxblock⟩ ;
⟨declarationxblock⟩ = ⟨labelxdeclarationxblock⟩
| ⟨constantxdeclarationxblock⟩
| ⟨resourcestringxdeclarationxblock⟩
| ⟨classxfuncxprocxdeclarationxblock⟩
| ⟨funcxprocxdeclarationxblock⟩
| ⟨typexdeclarationxblock⟩
| ⟨variablexdeclarationxblock⟩
| ⟨threadvariablexdeclarationxblock⟩
| ⟨exportsxclause⟩ ;
⟨funcxprocxdeclarationxblock⟩ = ⟨procedurexdeclaration ⟩
| ⟨functionxdeclaration⟩
| ⟨constructorxdeclaration⟩
| ⟨destructorxdeclaration⟩
| ⟨operatorxdeclaration⟩ ;
⟨statementxblock⟩ = ⟨compoundxstatement ⟩ ;](ref253x.png)