[fpc-pascal] Free Pascal Language Diagram

[Graeme Geldenhuys]

On 11/09/18 19:49, Anthony Walter wrote:
> 
> https://www.getlazarus.org/learn/language/lexical/
> 

Nice, but the mouse over animation is pretty annoying [and unnecessary]
though.

I've also been maintaining my own Object Pascal Grammar (using FPC's
objfpc mode only) in a EBNF (Extended Backus-Naur Form) like style. I
include it as part of the FPC Language Reference (INF help) included
with fpGUI.

It might look confusing to some that don't understand EBNF syntax, but
it really is pretty straight forward. Also with DocView's searching
ability and highlighting search matches is is very quick to find the
grammar of any Object Pascal language construct you are looking for.

Here is a snippet of the grammar...

========================================
Goal -> (Program | Package | Library | Unit)
Program -> [PROGRAM Ident ['(' IdentList ')'] ';']
           ProgramBlock '.'
Unit -> UNIT Ident [HintDirective] ';'
        InterfaceSection
        ImplementationSection
        InitSection '.'
Package -> PACKAGE Ident ';'
           [RequiresClause]
           [ContainsClause]
           END '.'
Library -> LIBRARY Ident ';'
           ProgramBlock '.'
ProgramBlock -> [UsesClause]
                Block
UsesClause -> USES IdentList ';'
HintDirective -> deprecated  [String]
              -> experimental
              -> library
              -> platform
              -> unimplemented
InterfaceSection -> INTERFACE
                    [UsesClause]
                    [InterfaceDecl]...
InterfaceDecl ->  ConstSection
              ->  TypeSection
              ->  VarSection
              ->  ExportedHeading
ExportedHeading -> ProcedureHeading ';' [Directive]
                -> FunctionHeading ';' [Directive]
ImplementationSection -> IMPLEMENTATION
                         [UsesClause]
                         [DeclSection]...
                         [ExportsStmt]...
Block -> [DeclSection]
         [ExportsStmt]...
         CompoundStmt
         [ExportsStmt]...
ExportsStmt -> EXPORTS ExportsItem [, ExportsItem]...
ExportsItem -> Ident [NAME|INDEX "'" ConstExpr "'"]
                     [INDEX|NAME "'" ConstExpr "'"]
DeclSection -> LabelDeclSection
            -> ConstSection
            -> TypeSection
            -> VarSection
            -> ProcedureDeclSection
LabelDeclSection -> LABEL LabelId
ConstSection -> CONST (ConstantDecl ';')...
ConstantDecl -> Ident '=' ConstExpr [HintDirective]
             -> Ident ':' TypeId '=' TypedConstant [HintDirective]
TypeSection -> TYPE (TypeDecl ';')
TypeDecl -> Ident '=' [TYPE] Type [HintDirective]
         -> Ident '=' [TYPE] RestrictedType [HintDirective]
TypedConstant -> (ConstExpr | ArrayConstant | RecordConstant)
ArrayConstant -> '(' TypedConstant ',' ')'
RecordConstant -> '(' RecordFieldConstant ';'... ')'
RecordFieldConstant -> Ident ':' TypedConstant

....snip....
========================================



Regards,
  Graeme

-- 
fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal
http://fpgui.sourceforge.net/

My public PGP key:  http://tinyurl.com/graeme-pgp