Simplify some grammar constructs.

A number of constructs in the grammar were only a single entry, or only
used once (or both). This CL inlines many of these single entry
constructs to the place of usage.

This makes it simpler to read the grammar requiring less jumping around
to determine what is permitted.

Author: dj2

chapters/grammar.adoc

@@ -100,11 +100,9 @@ endif::GLSL[]
 
 [role="bnf"]
 --
-_variable_identifier_ : ::
-    _IDENTIFIER_
 
 _primary_expression_ : ::
-    _variable_identifier_ +
+    _IDENTIFIER_ +
     _INTCONSTANT_ +
     _UINTCONSTANT_ +
     _FLOATCONSTANT_ +
@@ -116,7 +114,7 @@ endif::GLSL[]
 
 _postfix_expression_ : ::
     _primary_expression_ +
-    _postfix_expression_ _LEFT_BRACKET_ _integer_expression_ _RIGHT_BRACKET_ +
+    _postfix_expression_ _LEFT_BRACKET_ _expression_ _RIGHT_BRACKET_ +
     _function_call_ +
     _postfix_expression_ _DOT_ _FIELD_SELECTION_ +
     _postfix_expression_ _INC_OP_ +
@@ -128,16 +126,7 @@ FIELD_SELECTION includes members in structures, component selection for
 vectors and the 'length' identifier for the length() method
 ====
 
-_integer_expression_ : ::
-    _expression_
-
 _function_call_ : ::
-    _function_call_or_method_
-
-_function_call_or_method_ : ::
-    _function_call_generic_
-
-_function_call_generic_ : ::
     _function_call_header_with_parameters_ _RIGHT_PAREN_ +
     _function_call_header_no_parameters_ _RIGHT_PAREN_
 
@@ -171,6 +160,9 @@ _postfix_expression_.
 endif::ESSL[]
 ====
 
+_function_definition_ : ::
+    _function_prototype_ _compound_statement_no_new_scope_
+
 _function_identifier_ : ::
     _type_specifier_ +
     _postfix_expression_
@@ -276,11 +268,8 @@ _expression_ : ::
     _assignment_expression_ +
     _expression_ _COMMA_ _assignment_expression_
 
-_constant_expression_ : ::
-    _conditional_expression_
-
 _declaration_ : ::
-    _function_prototype_ _SEMICOLON_ +
+    _function_declarator_ _RIGHT_PAREN_ _SEMICOLON_ +
     _init_declarator_list_ _SEMICOLON_ +
     _PRECISION_ _precision_qualifier_ _type_specifier_ _SEMICOLON_ +
     _type_qualifier_ _IDENTIFIER_ _LEFT_BRACE_ _struct_declaration_list_
@@ -297,9 +286,6 @@ _identifier_list_ : ::
     _COMMA_ _IDENTIFIER_ +
     _identifier_list_ _COMMA_ _IDENTIFIER_
 
-_function_prototype_ : ::
-    _function_declarator_ _RIGHT_PAREN_
-
 _function_declarator_ : ::
     _function_header_ +
     _function_header_with_parameters_
@@ -318,10 +304,7 @@ _parameter_declarator_ : ::
 _parameter_declaration_ : ::
     _type_qualifier_ _parameter_declarator_ +
     _parameter_declarator_ +
-    _type_qualifier_ _parameter_type_specifier_ +
-    _parameter_type_specifier_
-
-_parameter_type_specifier_ : ::
+    _type_qualifier_ _type_specifier_ +
     _type_specifier_
 
 _init_declarator_list_ : ::
@@ -349,9 +332,6 @@ _fully_specified_type_ : ::
     _type_specifier_ +
     _type_qualifier_ _type_specifier_
 
-_invariant_qualifier_ : ::
-    _INVARIANT_
-
 _interpolation_qualifier_ : ::
     _SMOOTH_ +
 ifdef::GLSL[]
@@ -362,38 +342,32 @@ ifdef::ESSL[]
     _FLAT_
 endif::ESSL[]
 
-_layout_qualifier_ : ::
-    _LAYOUT_ _LEFT_PAREN_ _layout_qualifier_id_list_ _RIGHT_PAREN_
-
 _layout_qualifier_id_list_ : ::
     _layout_qualifier_id_ +
     _layout_qualifier_id_list_ _COMMA_ _layout_qualifier_id_
 
 _layout_qualifier_id_ : ::
     _IDENTIFIER_ +
 ifdef::GLSL[]
-    _IDENTIFIER_ _EQUAL_ _constant_expression_ +
+    _IDENTIFIER_ _EQUAL_ __conditional_expression__ +
 endif::GLSL[]
 ifdef::ESSL[]
     _IDENTIFIER_ _EQUAL_ _INTCONSTANT_ +
     _IDENTIFIER_ _EQUAL_ _UINTCONSTANT_ +
 endif::ESSL[]
     _SHARED_
 
-_precise_qualifier_ : ::
-    _PRECISE_
-
 _type_qualifier_ : ::
     _single_type_qualifier_ +
     _type_qualifier_ _single_type_qualifier_
 
 _single_type_qualifier_ : ::
     _storage_qualifier_ +
-    _layout_qualifier_ +
+    _LAYOUT_ _LEFT_PAREN_ _layout_qualifier_id_list_ _RIGHT_PAREN_ +
     _precision_qualifier_ +
     _interpolation_qualifier_ +
-    _invariant_qualifier_ +
-    _precise_qualifier_
+    _INVARIANT_ +
+    _PRECISE_
 
 _storage_qualifier_ : ::
     _CONST_ +
@@ -574,8 +548,7 @@ _precision_qualifier_ : ::
     _LOW_PRECISION_
 
 _struct_specifier_ : ::
-    _STRUCT_ _IDENTIFIER_ _LEFT_BRACE_ _struct_declaration_list_
-    _RIGHT_BRACE_ +
+    _STRUCT_ _IDENTIFIER_ _LEFT_BRACE_ _struct_declaration_list_ _RIGHT_BRACE_ +
     _STRUCT_ _LEFT_BRACE_ _struct_declaration_list_ _RIGHT_BRACE_
 
 _struct_declaration_list_ : ::
@@ -608,9 +581,6 @@ ifdef::ESSL[]
     _assignment_expression_
 endif::ESSL[]
 
-_declaration_statement_ : ::
-    _declaration_
-
 _statement_ : ::
     _compound_statement_ +
     _simple_statement_
@@ -621,7 +591,7 @@ Grammar Note: labeled statements for SWITCH only; 'goto' is not supported.
 ====
 
 _simple_statement_ : ::
-    _declaration_statement_ +
+    _declaration_ +
     _expression_statement_ +
     _selection_statement_ +
     _switch_statement_ +
@@ -682,7 +652,7 @@ _iteration_statement_ : ::
 
 _for_init_statement_ : ::
     _expression_statement_ +
-    _declaration_statement_
+    _declaration_
 
 _conditionopt_ : ::
     /* _empty_ */ +
@@ -719,9 +689,6 @@ ifdef::ESSL[]
     _declaration_
 endif::ESSL[]
 
-_function_definition_ : ::
-    _function_prototype_ _compound_statement_no_new_scope_
-
 --
 
 In general the above grammar describes a super set of the {slname}.