character   is a synonym for   char
   constant   is a synonym for   const
enumeration   is a synonym for   enum
       func   is a synonym for   function
    integer   is a synonym for   int
        ptr   is a synonym for   pointer
        ret   is a synonym for   returning
  structure   is a synonym for   struct
      indef   is a synonym for   indefinite
    noalias   is a synonym for   restrict

# program:
#   NOTHING
# | declare <declare>
# | cast <docast>
# | explain <explain>
# | set <set>
# | help <help> | '?' <help>
# | quit | exit

# explain:
#   ( <explaincast>
# | <explaincdecl>

# explaindecl:
#   <storage>? <ptrmodlist>? <type>? <cdecl> <ptrmodlist>?

# explaincast:
#   <ptrmodlist>? <type> <cast> ) NAME?

# docast:
#   NAME into <adecl>
# | <adecl>

# declare:
#   NAME as <storage>? <adecl>
# | <storage>? <adecl>

# adecl:
#   function ( <adecllist> returning <adecl>
# | function returning <adecl>
# | <ptrmodlist>? pointer to <adecl>
# | <ptrmodlist>? array NUMBER? of <adecl>
# | <ptrmodlist>? <type>

# ptrmodlist:
#   <ptrmod> <ptrmodlist>?

# ptrmod:
#   const
# | volatile
# | noalias
# | restrict
# | relaxed
# | strict
# | <shared>

# shared:
#   shared
# The following are valid only in C mode:
# | shared []
# | shared [*]
# | shared [NUMBER]
# Otherwise (english mode):
# | local
# | shared '('? blocksize? NUMBER ')'?
# | shared '('? blocksize? indefinite ')'?
# | shared '('? blocksize? automatic ')'?
# | shared '('? blocksize? cyclic ')'?

# cdecl:
#   <cdecl1>
# | * <ptrmodlist>? <cdecl>

# cdecl1:
#   ( <cdecl> ) <cdeclpost>*
# | NAME <cdeclpost>*

# cdeclpost:
#   ( )
# | ( <castlist>
# | [ ]
# | [ NUMBER ]

# cast:
#   <casthead>? <castpost>*

# casthead:
#   ( <castlist>
# | ( <cast>? )
# | ( <cast> ) ( <castlist>?
# | * <cast>?

# castpost:
#   [ ]
# | [ NUMBER ]

# type:
#   <typename>
# | <modlist> <typename>?
# | struct NAME
# | union NAME
# | enum NAME

# castlist:
#   <castlistitem> (, <castlistitem>)*
# | )

# castlistitem:
#   NAME
# | <ptrmodlist>? <type> <cast>

# adecllist:
#   <adecllistitem> (, <adecllistitem>)*
# | )

# adecllistitem:
#   NAME
# | NAME as <adecl>
# | <adecl>

# typename:
#   int | char | double | float | void

# modlist:
#   <modifier>
# | <modlist> <modifier>

# modifier:
#   short
# | long
# | unsigned
# | signed
# | <ptrmod>

# storage:
#   auto
# | extern
# | register
# | static