parser.pm

這是一個VHDL的parser目前版本為0.12

		expression_rule 
	reserved_word_select
		name_or_aggregate 
	'<='
	reserved_word_guarded(?) 
	delay_mechanism(?)
		waveform_when_choices_comma_waveform_when_choices
	';'

waveform_when_choices_comma_waveform_when_choices :
	waveform_when_choices
	comma_waveform_when_choices(s?)

comma_waveform_when_choices :
	','
	waveform_when_choices

waveform_when_choices :
	waveform_rule reserved_word_when choices_pipe_choices 

conditional_signal_assignment :
	name_or_aggregate 
	'<=' 
	reserved_word_guarded(?) 
	delay_mechanism(?)
		waveform_rule 
		when_boolean_expression_else_waveform_rule(s?)
	';' 

name_or_aggregate : 
	name | aggregate

when_boolean_expression_else_waveform_rule :
	reserved_word_when 
		boolean_expression 
	reserved_word_else
		waveform_rule

component_instantiation_statement :
	instantiation_label 
	':'
	entity_configuration_component
	generic_map_section(?)
	port_map_section(?)
	';'
	| <error>

	
entity_configuration_component :
	reserved_word_entity_and_entity_name_arch_name_in_parens |
	reserved_word_configuration_and_configuration_name |
	reserved_word_component_and_component_name 



reserved_word_entity_and_entity_name_arch_name_in_parens :
	reserved_word_entity 
		entity_name 
		architecture_identifier_in_parens(?)  

reserved_word_configuration_and_configuration_name :
	reserved_word_configuration 
		configuration_name 

reserved_word_component_and_component_name :
	reserved_word_component(?) 
		component_name  

architecture_identifier_in_parens :
	 '(' architecture_identifier ')'  

generate_statement :
	generate_label ':'
		for_identifier_in_range_or_if_boolean_expression
	reserved_word_generate
		generate_block_declarative_item_and_begin(?)
		concurrent_statement(s?)
	reserved_word_end 
	reserved_word_generate 
	generate_label(?) 
	';'

for_identifier_in_range_or_if_boolean_expression :
	for_identifier_in_range | if_boolean_expression

for_identifier_in_range :
	reserved_word_for 
		identifier 
	reserved_word_in 
		discrete_range

if_boolean_expression :
	reserved_word_if 
		boolean_expression

generate_block_declarative_item_and_begin :
	block_declarative_item(s?)
	reserved_word_begin

####################################################
####################################################
sequential_statement :
	  wait_statement 
	| assertion_statement
	| report_statement 
	| signal_assignment_statement 
	| variable_assignment_statement 
	| procedure_call_statement 
	| if_statement 
	| case_statement 
	| loop_statement 
	| next_statement 
	| exit_statement 
	| return_statement 
	| null_statement
	| <error>

wait_statement :
	label_followed_by_colon(?)
	reserved_word_wait
		on_list_of_signal(?)
	reserved_word_until_and_boolean_expression(?)
	reserved_word_for_and_time_expression(?)
	';'

reserved_word_until_and_boolean_expression :
	reserved_word_until 
		boolean_expression

reserved_word_for_and_time_expression :
	reserved_word_for 
		time_expression

on_list_of_signal :
 	reserved_word_on 
		signal_name_comma_signal_name

assertion_statement :
	label_followed_by_colon(?)
	reserved_word_assert boolean_expression
	reserved_word_report_and_expression_rule(?)
	reserved_word_severity_and_expression_rule(?)
	';'

reserved_word_report_and_expression_rule :
	reserved_word_report 
		expression_rule

reserved_word_severity_and_expression_rule :
	reserved_word_severity 
		expression_rule

report_statement :
	label_followed_by_colon(?)
	reserved_word_report_and_expression_rule 
	reserved_word_severity_and_expression_rule(?)
	';'

signal_assignment_statement :
	label_followed_by_colon(?)
	name_or_aggregate 
	'<='
	delay_mechanism(?)
	waveform_rule
	';'

delay_mechanism :
	reserved_word_transport | inertial_with_optional_reject_time

inertial_with_optional_reject_time :
	reserved_word_reject_and_time_expression(?) 
	reserved_word_inertial

reserved_word_reject_and_time_expression :
	reserved_word_reject 
		time_expression

waveform_rule :
	  reserved_word_unaffected 
	| waveform_item_comma_waveform_item

waveform_item_comma_waveform_item :
	waveform_item
	comma_waveform_item(s?)

comma_waveform_item :
	','
	waveform_item

waveform_item :
	  null_with_optional_after_time_expression 
	| value_expression_with_optional_time_expression

null_with_optional_after_time_expression :
	reserved_word_null 
	reserved_word_after_and_time_expression(?) 

value_expression_with_optional_time_expression :
	value_expression 
	reserved_word_after_and_time_expression(?)

reserved_word_after_and_time_expression :
	reserved_word_after 
	time_expression 

variable_assignment_statement :
	label_followed_by_colon(?)
		name_or_aggregate 
	':=' 
		expression_rule 
	';'

procedure_call_statement :
	label_followed_by_colon(?)
		procedure_name 
		subprogram_parameter_section(?) 
	';'
	| <error>

if_statement :
	label_followed_by_colon(?)
	reserved_word_if 
		boolean_expression 
	reserved_word_then
		sequential_statement(s)
	optional_elsif_section(s?)
	optional_else_section(?)
	reserved_word_end 
	reserved_word_if 
	if_label(?) 
	';'
	| <error>

optional_elsif_section :
	reserved_word_elsif 
		boolean_expression 
	reserved_word_then
		sequential_statement(s)

optional_else_section :
	reserved_word_else 
		sequential_statement(s)

case_statement :
	label_followed_by_colon(?)
	reserved_word_case expression_rule reserved_word_is
		when_choices_sequential_statement(s)
	reserved_word_end reserved_word_case case_label(?) ';'

when_choices_sequential_statement :
	reserved_word_when 
		choices_pipe_choices 
	'=>' 
		sequential_statement(s)

loop_statement :
	label_followed_by_colon(?)
	while_boolean_or_for_identifier_in_discrete_range
	reserved_word_loop
		sequential_statement(s)
	reserved_word_end reserved_word_loop loop_label(?) ';'

while_boolean_or_for_identifier_in_discrete_range :
	  reserved_word_while_and_boolean_expression
	| reserved_word_for_identifier_in_discrete_range

reserved_word_while_and_boolean_expression :
	reserved_word_while 
		boolean_expression

reserved_word_for_identifier_in_discrete_range :
	reserved_word_for 
		identifier 
	reserved_word_in 
		discrete_range

next_statement :
	label_followed_by_colon(?) 
	reserved_word_next 
	loop_label(?) 
	reserved_word_when_and_boolean_expression(?) 
	';'

exit_statement :
	label_followed_by_colon(?) 
	reserved_word_exit 
	loop_label(?) 
	reserved_word_when_and_boolean_expression(?) 
	';'

reserved_word_when_and_boolean_expression :
	reserved_word_when 
		boolean_expression

return_statement :
	label_followed_by_colon(?) 
	reserved_word_return 
	expression_rule(?) 
	';'

null_statement :
	label_followed_by_colon(?) 
	reserved_word_null 
	';'


####################################################
# E.7 Interfaces and Associations
####################################################
interface_list :
	interface_item_semicolon_interface_item

interface_item_semicolon_interface_item :
	interface_item
	semicolon_interface_item(s?)

semicolon_interface_item :
	';'
	interface_item

interface_item :
	  constant_interface 
	| signal_interface 
	| variable_interface 
	| file_interface


constant_interface :
	reserved_word_constant(?) 
		identifier_comma_identifier 
	':' 
	reserved_word_in(?) 
		subtype_indication 
		default_value(?) 
	| <error>


signal_interface :
	reserved_word_signal(?) 
		identifier_comma_identifier 
	':' 
		mode(?) 
		subtype_indication 
	reserved_word_bus(?) 
		default_value(?) 
	| <error>

variable_interface :
	reserved_word_variable(?) 
		identifier_comma_identifier 
	':' 
		mode(?) 
		subtype_indication 
		default_value(?) 
	| <error>

file_interface :
	reserved_word_file 
		identifier_comma_identifier 
	':'
		subtype_indication 
	| <error>

mode : 
	  reserved_word_inout 
	| reserved_word_out 
	| reserved_word_in 
	| reserved_word_buffer 
	| reserved_word_linkage 

association_list :
	actual_formal_comma_actual_formal
	| <error>

actual_formal_comma_actual_formal :
	actual_part_with_optional_formal_part
	comma_actual_part_with_optional_formal_part(s?)
	| <error>

comma_actual_part_with_optional_formal_part :
	','
	actual_part_with_optional_formal_part
	| <error>

actual_part_with_optional_formal_part :
	formal_part_and_arrow(?) 
		actual_part
	| <error>

formal_part_and_arrow :
	formal_part '=>'
	| <error>

formal_part :
	  generic_name 
	| port_name 
	| parameter_name 
	| function_name generic_port_parameter_selection 
	| type_mark generic_port_parameter_selection 
	| <error>

generic_port_parameter_selection :
	'(' generic_name_port_name_parameter_name ')'
	| <error>

generic_name_port_name_parameter_name :
	generic_name | port_name | parameter_name
	| <error>

actual_part :
	  expression_rule 
	| variable_name 
	| reserved_word_open 
	| function_name_signal_name_or_variable_name_selection 
	| type_mark_signal_name_or_variable_name_selection
	| <error>


function_name_signal_name_or_variable_name_selection :
	function_name
	signal_name_or_variable_name_in_parens

type_mark_signal_name_or_variable_name_selection :
	type_mark
	signal_name_or_variable_name_in_parens

signal_name_or_variable_name_in_parens :
	'(' signal_name_or_variable_name ')'

signal_name_or_variable_name :
	signal_name | variable_name

####################################################
# E.8 Expressions
####################################################
boolean_expression :
	expression_rule

static_expression :
	expression_rule


expression_rule : 
	relation 
	logic_relation(s?)

logic_relation : 
	logic_relation_operator
	relation

logic_relation_operator : 
	  reserved_word_nand 
	| reserved_word_xnor 
	| reserved_word_and 
	| reserved_word_nor 
	| reserved_word_xor 
	| reserved_word_or 

relation :
	shift_expression 
	relation_shift_expression(?)

relation_shift_expression :
	relation_operator 
	shift_expression 

relation_operator : 
	  '/=' 
	| '<=' 
	| '>='
	| '=' 
	| '>' 
	| '<' 

shift_expression :
	simple_expression 
	shift_simple_expression(?)

shift_simple_expression :
	 shift_operator
	 simple_expression 

shift_operator : 
	  reserved_word_sll 
	| reserved_word_srl 
	| reserved_word_sla 
	| reserved_word_sra 
	| reserved_word_rol
	| reserved_word_ror 


simple_expression :
	sign(?) term optional_term(s?) 

sign :
	'+' | '-' 

optional_term :
	add_or_concat_operator term 

add_or_concat_operator :
	  '+' 
	| '-' 
	| '&'

term :
	factor
	optional_factor(s?) 

optional_factor :
	multiply_operator factor 

multiply_operator :
	  '*' 
	| '/' 
	| reserved_word_mod 
	| reserved_word_rem

factor :
	  reserved_word_abs_and_primary 
	| reserved_word_not_and_primary
	| primary_exp_primary 

reserved_word_abs_and_primary :
	reserved_word_abs primary

reserved_word_not_and_primary :
	reserved_word_not primary

primary_exp_primary :
	primary exponent_primary(?) 

exponent_primary :
	'**' primary 


# notes:
#
# the rules for "primary" is not mutually exclusive:
# there are rules that apply such that a given input text
# could be one of two different possible interpretations.
#
# there is no way to distinguish between the two possibilities
# by simply looking at the token being examined.
#
# 1)
#
# aggregate : '(' optional_choice_arrow(?) expression_rule [ ',' repeat ] ')'
# expression in paren : '(' expression_rule ')' 
#
# therefore an aggregate with one entry and no choice arrow is
# indistinguishable from an expression in paren.
#
#
# 2)
#
#  function_call       # token ( param=>(?) value [,repeat])(?)
#  literal->identifier # token
#
# therefore a function call with no input parameters is
# indistinguishable from a literal identifier.


primary : 
	  new_qualified_expression  # 'new' token ' ( yada )
	| new_subtype_indication    # 'new' token
	| qualified_expression   # token ' ( yada )
	| function_call 	 # token ( param=>(?) value [,repeat])(?)
	| literal
	| aggregate	# '(' choice=>(?) expression [,repeat] ')'
	| expression_rule_in_parens 
	| name 

new_qualified_expression :
	reserved_word_new 
	qualified_expression

new_subtype_indication :
	reserved_word_new 
	subtype_indication

qualified_expression :
	  type_mark_tick_aggregate   
	| type_mark_tick_expression  

type_mark_tick_expression :
	type_mark "'" '(' expression_rule ')'

type_mark_tick_aggregate :
	type_mark "'" aggregate