Ez a fejezet megadja a Theta nyelvtanát.
program units, routine specifications (rutin specifikációk), and equates (egyenlőségek)
<program_unit> -> <routine_interface> | <equate> | <type_interface> | <module>
<routine_interface> -> <proc_interface> | <iter_interface>
<equate> -> <idn> "=" <expr> | <idn> "=" <type_designator>
<proc_interface> -> <idn> [<parms>] <formal_args> [<returns>] [<signals>] [<where>]
<iter_interface> -> <idn> [<parms>] <formal_args> <yields> [<signals>] [<where>]
<parms> -> "[" <idn_list> "]"
<idn_list> -> <idn> ["," <idn>]*
<formal_args> -> "(" [<decl> ["," <decl>]*] ")"
<decl> -> <idn_list> ":" <type_designator>
<returns> -> returns "(" <type_list> ")"
<type_list> -> <type_designator> ["," <type_designator>]*
<yields> -> yields "(" <type_list> ")"
<signals> -> signals "(" <exception> ["," <exception>]* ")"
<exception> -> <name> ["(" <type_list> ")"]
<name> -> <idn>
<where> -> where <restriction> ["," <restriction>]*
<restriction> -> <idn> has <nonparam_interface> ["," <nonparam_interface>]*
<nonparam_interface> -> <idn> <nonparam_proc_sig> | <idn> <nonparam_iter_sig>
<nonparam_proc_sig> -> "(" [<type_list>] ")" [<returns>] [<signals>]
<nonparam_iter_sig> -> "(" [<type_list>] ")" <yields> [<signals>]
type specifications (típus specifikációk)
<type_interface> -> <idn> "=" type [<parms>] [<supertypes>] [<where>]
[<interface_or_equate>]*
end <idn>
<supertypes> -> "<" <superinfo> ["," <superinfo>]*
<superinfo> -> <type_designator> ["{" <renames> ["," <renames>]* "}" ]
<renames> -> <idn> for <idn>
<interface_or_equate> -> <routine_interface> | <equate>
type designators (típus jelölések)
<type_designator> -> <simple_type_desig> | <routine_type_desig> | <parm_type_desig>
| <tagged_type_desig>
<simple_type_desig> -> <idn> | 'null' | 'bool' | 'char' | 'int' | 'real' | 'string' | 'any'
<routine_type_desig> -> proc <nonparam_proc_sig> | iter <nonparam_iter_sig>
<parm_type_desig> -> <parm_type> <actual_parms>
<parm_type> -> <idn> | 'array' | 'sequence' | 'vector' | 'maybe'
<actual_parms> -> "[" <type_list> "]"
<tagged_type_desig> -> <tagged_type> "[" <field> ["," <field>]* "]"
<tagged_type> -> 'record' | 'struct' | 'oneof'
<field> -> <idn_list> ":" <type_designator>
modules (modulok)
<module> -> module [<implements>] [<impl_elt>]* end
<implements> -> implements <exported_item> ["," <exported_item>]*
<exported_item> -> <idn> [ "{" <idn_list> "}" ] | <idn> <actual_parms> "{" <idn_list> "}"
<impl_elt> -> <routine_def> | <class_def> | <maker_def> | <equate>
<routine_def> -> <routine_interface> <body> end <idn>
<maker_def> -> <maker_interface> <body> end <idn>
<maker_interface> -> <idn> [<parms>] <formal_args> <makes> [<signals>] [<where>]
<makes> -> makes "(" <type_designator> ")"
<body> -> [<equate>]* [<statement>]*
<class_def> -> <idn> "=" class [<parms>] [<for_type>] [<inherits>]
[<where>] [<provides>] [<hides>]
[<equate_or_ivar_decl>]*
[<equate_or_routine_def>]*
end <idn>
<for_type> -> for <type_designator>
<inherits> -> inherits <type_designator> ["{" <renames> ["," <renames>]* "}"]
<provides> -> provides <idn_list>
<hides> -> hides <idn_list>
<equate_or_ivar_decl> -> <equate> | <ivar_decl>
<ivar_decl> -> <decl> | <decl_with_impls>
<decl_with_impls> -> <idn> ":" <type_designator> implements <idn> ["," <idn>]
<equate_or_routine_def> -> <equate> | <routine_def>
statements (utasítások)
<statement> -> <decl>
| <lhs> ":=" <expr> ["," <expr>]*
| <lhs> ":=" <invoc>
| <simple_invoc>
| <primary> "[" <expr> "]" ":=" <expr>
| return ["(" <expr> ["," <expr>]* ")"]
| yield "(" <expr> ["," <expr>]* ")"
| signal <name> ["(" <expr> ["," <expr>]* ")"]
| exit <name> ["(" <expr> ["," <expr>]* ")"]
| if <expr> then <body> [elseif <expr> then <body>]* [else <body>] end
| while <expr> do <body> end
| for <for_idns> in <invoc> do <body> end
| break
| continue
| begin <body> end
| tagcase <expr> <tag_arm> [<tag_arm>]* [others ":" <body>] end
| typecase <expr> <type_arm> [<type_arm>]* [others ":" <body>] end
| <statement> except [<handler>]* [others ["(" <idn> ":" 'string' ")"] ":" <body>] end
| <statement> resignal <name> ["," <name>]*
| make "{" [<ivar_inits>] "}" [then <body> end]
<lhs> -> <var> ["," <var>]* | <decl> ["," <decl>]*
<var> -> <idn> | <primary> "." <idn>
<invoc> -> <expr> "(" [<args>] ")"
<args> -> <expr> ["," <expr>]* ["," <varying_args>] | <varying_args>
<varying_args> -> .. | .. <expr> ["," <expr>]*
<simple_invoc> -> <primary> "(" [<args>] ")"
<for_idns> -> <idn_list> | <decl> ["," <decl>]*
<tag_arm> -> when <name> ["," <name>]* ["(" <idn> ":" <type_designator> ")"] ":" <body>
<type_arm> -> when <type_designator> ["(" <idn> ")"] ":" <body>
<handler> -> when <name> ["," <name>]* ["(" <decl> ["," <decl>]* ")"] ":" <body>
<ivar_inits> -> <field_inits> ";" <maker_invoc> | <field_inits> | <maker_invoc>
<field_inits> -> <field_init> ["," <field_init>]*
<field_init> -> <idn> ":=" <expr>
<maker_invoc> -> <idn> [<actual_parms>] "(" [<args>] ")"
expressions (kifejezések)
<expr> -> <simple_expr>
| <expr> "." <idn>
| <expr> "." <method_idn>
| <invoc>
| <expr> "[" <expr> "]"
| "~" <expr>
| "-" <expr>
| <expr> <binary_op> <expr>
| "(" <expr> ")"
<primary> -> <simple_expr>
| <primary> "." <idn>
| <primary> "." <method_idn>
| <simple_invoc>
| <primary> "[" <expr> "]"
<simple_expr> -> <literal>
| <idn> [<actual_parms>]
| self
| <method_idn>
| <tagged_type_desig> "{" <field_inits> "}"
| <type_designator> "{" [<ivar_inits>] "}"
| bind "(" <expr> <bind_args> ")"
<method_idn> -> ["^"] <idn> [<actual_parms>]
<bind_args> -> ["," <bind_arg>]* ["," <varying_args>]
<bind_arg> -> <expr> | "*"
<literal> -> 'nil'
| 'true'
| 'false'
| <int_literal>
| <char_literal>
| <real_literal>
| <string_literal>
<binary_op> -> "**" | "//" | "/" | "*" | "||" | "+" | "-" | "<" | "<="
| "=" | ">=" | ">" | "==" | "~=" | "&" | "|"