% @doc
% gsc_bst = ast second attempt but prefix so tab complete
%
% from docs/sophia/so_syntax.md:
%
% File ::= Block(TopDecl)
%
% TopDecl ::= ['payable'] ['main'] 'contract' Con [Implement] '=' Block(Decl)
%           | 'contract' 'interface' Con [Implement] '=' Block(Decl)
%           | 'namespace' Con '=' Block(Decl)
%           | '@compiler' PragmaOp Version
%           | 'include' String
%           | Using
%
% Implement ::= ':' Sep1(Con, ',')
%
% Decl ::= 'type'     Id ['(' TVar* ')'] '=' TypeAlias
%        | 'record'   Id ['(' TVar* ')'] '=' RecordType
%        | 'datatype' Id ['(' TVar* ')'] '=' DataType
%        | 'let'      Id [':' Type]      '=' Expr
%        | (EModifier* 'entrypoint' | FModifier* 'function') Block(FunDecl)
%        | Using
%
% FunDecl ::= Id ':' Type                             // Type signature
%           | Id Args [':' Type] '=' Block(Stmt)      // Definition
%           | Id Args [':' Type] Block(GuardedDef)    // Guarded definitions
%
% GuardedDef ::= '|' Sep1(Expr, ',') '=' Block(Stmt)
%
% Using ::= 'using' Con ['as' Con] [UsingParts]
% UsingParts ::= 'for' '[' Sep1(Id, ',') ']'
%              | 'hiding' '[' Sep1(Id, ',') ']'
%
% PragmaOp ::= '<' | '=<' | '==' | '>=' | '>'
% Version  ::= Sep1(Int, '.')
%
% EModifier ::= 'payable' | 'stateful'
% FModifier ::= 'stateful' | 'private'
%
% Args ::= '(' Sep(Pattern, ',') ')'
-module(gsc_bst).

-compile([export_all, nowarn_export_all]).
-include("$gsc_include/gsc.hrl").

%-record(bst_nyi, {tokens :: [tk()]).
%
%% ['payable'] ['main'] 'contract' Con [Implement] '=' Block(Decl)
%-record(bst_ct,
%        {payable    = none :: none | boolean(),
%         main       = none :: none | boolean(),
%         name       = none :: none | string(),
%         impl       = none :: none | [string()],
%         eq         = none :: none | '=',
%         decls      = none :: none | [decl()]}).
%
%% 'contract' 'interface' Con [Implement] '=' Block(Decl)
%-record(bst_iface,
%        {payable    = none :: none | boolean()
%         name       = none :: none | string(),
%         impl       = none :: none | [string()],
%         eq         = none :: none | '=',
%         decls      = none :: none | [decl()]}).
%
%
%
%%   File ::= Block(TopDecl)
%gulp(file, Tokens) ->
%    gulp({block, top_decl}, Tokens);
%%   TopDecl ::= ['payable'] ['main'] 'contract' Con [Implement] '=' Block(Decl)
%%             | 'contract' 'interface' Con [Implement] '=' Block(Decl)
%%             | 'namespace' Con '=' Block(Decl)
%%             | '@compiler' PragmaOp Version
%%             | 'include' String
%%             | Using
%gulp(top_decl, [#tk{string = S} | Rest]) ->
%    case strings(3, Tokens) of
%        ["payable", "contract", "interface"] ->
%            gulp_ct(#bst_iface{payable = true, main = true}, drop(3, Tokens));
%        ["payable", "contract",  _] ->
%            gulp_ct(#bst_ct{payable = true, main = false}, drop(2, Tokens));
%        ["contract" | _] ->
%    gulp({oneof, [bst_iface, bst_ct, bst_nyi]}, Tokens);
%gulp(bst_ct, Tokens) ->
%gulp(top_decl, Tokens) ->