tree-sitter-hcl.ebnf

//
// From tree-sitter-hcl/src/grammar.json
//
//
// EBNF to generate railroad diagram at 
//      (IPV6) https://www.bottlecaps.de/rr/ui
//      (IPV4) https://rr.red-dove.com/ui
//

config_file ::=
	 body | object

body ::=
	 ( attribute | block )+

attribute ::=
	 identifier '=' expression

block ::=
	 identifier ( string_lit | identifier )* block_start body? block_end

block_start ::=
	 '{'

block_end ::=
	 '}'

identifier ::=
	 ( ( '\p{ID_Start}' | '_' ) ( '\p{ID_Continue}' | '-' )* )

expression ::=
	 _expr_term | conditional

_expr_term ::=
	 literal_value
	| template_expr
	| collection_value
	| variable_expr
	| function_call
	| for_expr
	| operation
	| _expr_term index
	| _expr_term get_attr
	| _expr_term splat
	| '(' expression ')'

literal_value ::=
	 numeric_lit
	| bool_lit
	| null_lit
	| string_lit

numeric_lit ::=
	 [0-9]+('.'[0-9]+([eE][-+]?[0-9]+)?)?
	| '0x'[0-9a-zA-Z]+

bool_lit ::=
	 'true'
	| 'false'

null_lit ::=
	 'null'

string_lit ::=
	 quoted_template_start template_literal? quoted_template_end

collection_value ::=
	 tuple
	| object

_comma ::=
	 ','

tuple ::=
	 tuple_start _tuple_elems? tuple_end

tuple_start ::=
	 '['

tuple_end ::=
	 ']'

_tuple_elems ::=
	 expression ( _comma expression )* _comma?

object ::=
	 object_start _object_elems? object_end

object_start ::=
	 '{'

object_end ::=
	 '}'

_object_elems ::=
	 object_elem ( _comma? object_elem )* _comma?

object_elem ::=
	 expression ( '=' | ':' ) expression

index ::=
	 new_index
	| legacy_index

new_index ::=
	 '[' expression ']'

legacy_index ::=
	 '.' [0-9]+

get_attr ::=
	 '.' identifier

splat ::=
	 attr_splat
	| full_splat

attr_splat ::=
	 '.*' ( get_attr | index )*

full_splat ::=
	 '[*]' ( get_attr | index )*

for_expr ::=
	 for_tuple_expr
	| for_object_expr

for_tuple_expr ::=
	 tuple_start for_intro expression for_cond? tuple_end

for_object_expr ::=
	 object_start for_intro expression '=>' expression ellipsis? for_cond? object_end

for_intro ::=
	 'for' identifier ( ',' identifier )? 'in' expression ':'

for_cond ::=
	 'if' expression

variable_expr ::=
	 identifier

function_call ::=
	 identifier _function_call_start function_arguments? _function_call_end

_function_call_start ::=
	 '('

_function_call_end ::=
	 ')'

function_arguments ::=
	 expression ( _comma expression )* ( _comma | ellipsis )?

ellipsis ::=
	 '...'

conditional ::=
	 expression '?' expression ':' expression

operation ::=
	 unary_operation
	| binary_operation

unary_operation ::=
	 ( '-' | '!' ) _expr_term

binary_operation ::=
	 _expr_term ( '*' | '/' | '%' ) _expr_term
	| _expr_term ( '+' | '-' ) _expr_term
	| _expr_term ( '>' | '>=' | '<' | '<=' ) _expr_term
	| _expr_term ( '==' | '!=' ) _expr_term
	| _expr_term ( '&&' ) _expr_term
	| _expr_term ( '||' ) _expr_term

template_expr ::=
	 quoted_template
	| heredoc_template

quoted_template ::=
	 quoted_template_start _template? quoted_template_end

heredoc_template ::=
	 heredoc_start heredoc_identifier _template? heredoc_identifier

heredoc_start ::=
	 '<<'
	| '<<-'

strip_marker ::=
	 '~'

_template ::=
	 ( template_interpolation | template_directive | template_literal )+

template_literal ::=
	 _template_literal_chunk+

template_interpolation ::=
	 template_interpolation_start strip_marker? expression? strip_marker? template_interpolation_end

template_directive ::=
	 template_for
	| template_if

template_for ::=
	 template_for_start _template? template_for_end

template_for_start ::=
	 template_directive_start strip_marker? 'for' identifier ( ',' identifier )? 'in' expression strip_marker? template_directive_end

template_for_end ::=
	 template_directive_start strip_marker? 'endfor' strip_marker? template_directive_end

template_if ::=
	 template_if_intro _template? ( template_else_intro _template? )? template_if_end

template_if_intro ::=
	 template_directive_start strip_marker? 'if' expression strip_marker? template_directive_end

template_else_intro ::=
	 template_directive_start strip_marker? 'else' strip_marker? template_directive_end

template_if_end ::=
	 template_directive_start strip_marker? 'endif' strip_marker? template_directive_end

comment ::=
	 ( '#' '.'* | '//' '.'* | '/*' [^*]*'\'*+([^/*][^*]*'\'*+)* '/' )

_whitespace ::=
	 [ #x09#x0A#x0B#x0C#x0D]