. Syntax of the Pascal Programming Language
.See ASCII
ASCII::=http://www/dick/samples/comp.text.ASCII.html.

.See LEXEMES
LEXEMES::=http://www/dick/samples/pascal.lexicon.html.

.Open SYNTAX

. Programs and Blocks
program ::= $program_heading semicolon program_block,
.As_is 	program hi(out); begin writeln('Hello, World!'); end.
program_heading::="program" identifier ("(" $O( program_parameters) ")" |),
.As_is 	program merge(infile1, infile2, mergedfile);
program_block::= $block ".",
.As_is 	begin writeln('Hi'); writeln('there!'); end .
block::= $label_declarations $constant_definitions $type_definitions $variable_declarations $procedure_function_declarations $statement_part,
.As_is 	const n=1; m=2; begin writeln(m+n); end
program_parameters::= $List(identifier),
.As_is 	in,out,waveItAllAbout
.Open Declarations and Definitions
label_declarations::= $O("label" $List($label) semicolon ),
label::= $digit_sequence,
.As_is 	label 1,2,3,911;
constant_definitions::= $O("const" $S($constant_definition) semicolon),
constant_definition::= identifier "=" constant,

type_definitions::= $O("type" $type_definition semicolon #($type_definition semicolon) ),
type_definition::= identifier "=" type_denoter,

variable_declarations::= $O("var" $variable_declaration semicolon #($variable_declaration semicolon) ),
variable_declaration::= $identifier_list ":" $type_denoter,

procedure_function_declarations::= #( $procedure_declaration | $function_declaration ) semicolon,

.Open Subprogram Declarations
subprogram_declaration::=$procedure_declaration | $function_declaration.
. Procedure Declarations
procedure_declaration::= $procedure_heading semicolon $directive | $procedure_identification semicolon $procedure_block | $procedure_heading semicolon $procedure_block,
procedure_heading::= "procedure" identifier $O($formal_parameter_list),
procedure_identification::= "procedure" $procedure_identifier,
procedure_block::= $block,
procedure_identifier::= identifier,

directive::= letter #(letter | digit),
type_denoter::= $type_identifier | $new_type,
. Function Declarations
function_declaration::= $function_heading semicolon $directive | $function_identification semicolon $function_block | $function_heading semicolon $function_block,
function_heading::= "function" identifier ($formal_parameter_list |) ":" $result_type,
function_block::= $block.
. Formal Parameters and Arguments
formal_parameter_list::= $formal_parameter_section #( semicolon $formal_parameter_section),
formal_parameter_section::= $value_parameter_specification | $variable_parameter_specification | $procedural_parameter_specification | $functional_parameter_specification | $conformant_array_parameter_specification,

value_parameter_specification::= $identifier_list ":" $type_identifier,
variable_parameter_specification::= "var" $identifier_list ":" $type_identifier,
procedural_parameter_specification::= $procedure_heading,
functional_parameter_specification::= $function_heading,

conformant_array_parameter_specification::= $value_conformant_array_specification | $variable_conformant_array_specification,
value_conformant_array_specification::= $identifier_list ":" $conformant_array_schema,
variable_conformant_array_specification::= "var" $identifier_list ":" $conformant_array_schema,
conformant_array_schema::= $packed_conformant_array_schema | $unpacked_conformant_array_schema,
packed_conformant_array_schema::= "packed" "array" $O($index_type_specification ) "of" $type_identifier,
unpacked_conformant_array_schema::= "array" $O($index_type_specification #(semicolon $index_type_specification) ) "of" $type_identifier | $conformant_array_schema,
index_type_specfication::= identifier ".." identifier ":" $ordinal_type_identifier,
.Close
.Close
. Constants
constant::= $signed_number | $constant_identifier | $character_string,
unsigned_constant::= $unsigned_number | $character_string | $constant_identifier | "nil",
unsigned_number::= $unsigned_integer | $unsigned_real,
constant_identifier::= identifier,
. Types
type_identifier::= identifier,
new_type::= $new_ordinal_type | $new_structured_type | $new_pointer_type,

result_type::= $simple_type_identifier | $pointer_type_identifier,

new_ordinal_type::= $enumerated_type | $subrange_type,

new_structured_type::= $O("packed") $unpacked_structured_type,

new_pointer_type::= "^" $domain_type,

simple_type_identifier::= $type_identifier,

pointer_type_identifier::= $type_identifier,

enumerated_type::= $identifier_list,

subrange_type::= $constant ".." $constant,

unpacked_structured_type::= $array_type | $record_type | $set_type | $file_type,

domain_type::= $type_identifier,

array_type::= "array" #($index_type #("," $index_type) ) "of" $component_type,

set_type::= "set of" $base_type,

file_type::= "file of" $component_type,

index_type::= $ordinal_type,

component_type::= $type_denoter,

base_type::= $ordinal_type,
ordinal_type::= $new_ordinal_type | $ordinal_type_identifier,
ordinal_type_identifier::= $type_identifier,

record_type::= "record" $field_list "end",
record_section::= $identifier_list ":" $type_denoter,
field_list::= $O( $fixed_part #( semicolon $variant_part ) ,
fixed_part::= $record_section #( semicolon $record_section),
variant_part::= "case" $variant_selector "of"  $variant #( semicolon $variant),
variant_selector::= $O( $tag_field ":" ) $tag_type,
variant::= $case_constant_list ":" $field_list,
tag_field::= $identifier,
tag_type::= $ordinal_type_identifier,
case_constant_list::= $case_constant #( "," $case_constant),
case_constant::= $constant,

. Statements
procedure_statement::= $procedure_identifier $O($actual_parameter_list ) | $IO_procedure_statement,
IO_procedure_statement::= "read" read_parameter_list | "readln" readln_parameter_list | "write" write_parameter_list | "writeln" writeln_parameter_list,
actual_parameter_list::= $actual_parameter #( "," $actual_parameter),
optional_file::=$O($file_variable ","),
read_parameter_list::=  $optional_file $variable_access #( "," $variable_access),
readln_parameter_list::= $O( $optional_file $variable_access #( "," $variable_access) ),
write_parameter_list::= $optional_file $write_parameter #( "," $write_parameter),
writeln_parameter_list::=  $O($optional_file $write_parameter #( "," $write_parameter) ),
actual_parameter::= $expression | $variable_access | $procedure_identifier | $function_identifier,
file_variable::= $variable_access,
variable_access::= $entire_variable | $component_variable | $identified_variable | $buffer_varible,
write_parameter::= $expression $O( ":" O(":" $expression ) ),
statement_part::= $compound_statement,
compound_statement::= "begin" $statement_sequence "end",
statement_sequence::= $statement #($semicolon $statement),
statement::= $O( $label ":" ) ($simple_statement | $structured_statement),
simple_statement::= $empty_statement | $assignment_statement | $procedure_statement | $goto_statement,
structured_statement::= $compound_statement | $conditional_statement | $repetitive_statement | $with_statement,
empty_statement::=,
assignment_statement::= $variable_access | $function_identifier ":=" $expression,
goto_statement::= "goto" $label,
conditional_statement::= $if_statement | $case_statement,
repetitive_statement::= $repeat_statement | $while_statement | $for_statement,
loop::= $repeat_statement | $while_statement | $for_statement,
with_statement::= "with" $record_variable_list "do" $statement,
if_statement::= "if" $boolean_expression "then" $statement $O($else_part ),
case_statement::= "case" $case_index "of" $case_list_element #(semicolon $case_list_element) $O(semicolon |) "end",
repeat_statement::= "repeat" $statement_sequence "until" $boolean_expression,
while_statement::= "while" $boolean_expression "do" $statement,
for_statement::= "for" $control_variable ":=" $initial_value ("to" | "downto") $final_value "do" $statement,
record_variable_list::= $record_variable #("," $record_variable),
boolean_expression::= $expression,
else_part::= "else" $statement,
case_index::= $expression,
case_list_element::= $case_constant_list ":" $statement,
control_variable::= $entire_variable,
initial_value::= $expression,
final_value::= $expression,

. Expressions and Variables
expression::= $simple_expression #($relational_operator $simple_expression ),
function_identifier::= $identifier,
entire_variable::= $variable_identifier,
component_variable::= $indexed_variable | $field_designator,
identified_variable::= $pointer_variable "^",
buffer_variable::= $file_variable "^",
simple_expression::= $O($sign) $term #($adding_operator $term),
variable_identifier::= identifier,
indexed_variable::= $array_variable "[" $O($index_expression #("," $index_expression) ) "]" ,
field_designator::= $record_variable "." $field_specifier | $field_designator_identifier,
pointer_variable::= $variable_access,
term::= $factor #(multiplying_operator $factor),
array_variable::= $variable_access,
index_expression::= $expression,
record_variable::= $variable_access,
field_specifier::= $field_identifier,
field_designator_identifier::= $identifier,
factor::= $variable_access | $unsigned_constant | $function_designator | $set_constructor | $expression | "not" $factor, | $bound_identifier,
field_identifier::= $identifier,
set_constructor::= $O( #($member_designator #("," $member_designator)) ),
bound_identifier::= $identifier,
member_designator::= $expression #(".." $expression),
function_identification::= "function" $function_identifier,
function_designator::= $function_identifier $O($actual_parameter_list ),
.Close SYNTAX
. Notation
$O(X)::= empty | X.
#(X)::= `any number of X`.
S(X)::= X #(";" X).
List(X)::= X #("," X).
. Semantics and UML Model
.See https://gforge.inria.fr/scm/viewvc.php/*checkout*/AtlanticRaster/all/Pascal.png?root=atlantic-zoos