mpw-shell/phase2-parser.lemon
2016-02-04 21:57:17 -05:00

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/*
>, < redirection is handled later, after environment expansion.
(also, redirection can be in the middle of a command.)
*/
%include {
#include "phase2.h"
#include "command.h"
#define LEMON_SUPER phase2_parser
#include "phase2-parser.h"
}
%code {
std::unique_ptr<phase2_parser> phase2_parser::make() {
return std::make_unique<yypParser>();
}
bool phase2_parser::continuation() const {
yypParser *self = (yypParser *)this;
for (const auto &e : *self) {
if (e.major == BEGIN) return true;
if (e.major == LPAREN) return true;
if (e.major == IF) return true;
if (e.major == AMP_AMP) return true;
if (e.major == PIPE_PIPE) return true;
}
return false;
}
}
%left PIPE_PIPE AMP_AMP.
%left PIPE.
%token_type {std::string}
%default_type {command_ptr}
%type start {void}
%type command_list {void}
/* these are put into a queue for immmediate execution */
start ::= command_list.
command_list ::= .
command_list ::= command_list sep .
command_list ::= command_list command(C) sep . {
if (C) command_queue.emplace_back(std::move(C));
}
/*
compound_list is identical to command_list, but it is not executed immediately.
*/
%type compound_list { command_ptr_vector }
compound_list ::= .
compound_list(RV) ::= compound_list(L) sep. {
RV = std::move(L);
}
compound_list(RV) ::= compound_list(L) command(C) sep . {
RV = std::move(L);
if (C) RV.emplace_back(std::move(C));
}
sep ::= SEMI.
sep ::= NL.
%type command { command_ptr }
/* nb -- ||, &&, | -- both sides are optional. This does not. */
command(RV) ::= command(L) PIPE_PIPE opt_nl command(R). {
RV = std::make_unique<or_command>(std::move(L), std::move(R));
}
command(RV) ::= command(L) AMP_AMP opt_nl command(R). {
RV = std::make_unique<and_command>(std::move(L), std::move(R));
}
/*
command(RV) ::= command PIPE opt_nl command. {
RV = std::make_unique<pipe_command>(std::move(L), std::move(R));
}
*/
command(RV) ::= term(T). { RV = std::move(T); }
term(RV) ::= COMMAND(C). { RV = std::make_unique<simple_command>(std::move(C)); }
term(RV) ::= EVALUATE(C). { RV = std::make_unique<evaluate_command>(std::move(C)); }
term(RV) ::= if_command(C). { RV = std::move(C); }
term(RV) ::= begin_command(C). { RV = std::move(C); }
term(RV) ::= paren_command(C). { RV = std::move(C); }
/*
* fall back to an end error. w/o fallback, it will cause a parse conflict.
*/
/*
%fallback ERROR END RPAREN ELSE ELSE_IF.
term(RV) ::= ERROR(C). {
RV = std::make_unique<error_command>(@C, std::move(C));
}
*/
/* compound list ends with a separator. paren command does not need the final separator */
%type paren_list { command_ptr_vector }
paren_list(RV) ::= compound_list(L) . {
RV = std::move(L);
}
paren_list(RV) ::= compound_list(L) command(C) . {
RV = std::move(L);
RV.emplace_back(std::move(C));
}
paren_command(RV) ::= LPAREN(T) paren_list(L) RPAREN(E). {
RV = std::make_unique<begin_command>(@T, std::move(L), std::move(T), std::move(E));
}
begin_command(RV) ::= BEGIN(T) sep compound_list(L) END(E). {
RV = std::make_unique<begin_command>(@T, std::move(L), std::move(T), std::move(E));
}
if_command(RV) ::= IF(I) sep compound_list(L) END(E). {
if_command::clause_vector_type v;
v.emplace_back(std::make_unique<if_else_clause>(IF, std::move(L), std::move(I)));
RV = std::make_unique<if_command>(
std::move(v),
std::move(E)
);
}
if_command(RV) ::= IF(I) sep compound_list(L) else_command(EC) END(E). {
if_command::clause_vector_type v;
v.emplace_back(std::make_unique<if_else_clause>(IF, std::move(L), std::move(I)));
for(auto &c : EC) { v.emplace_back(std::move(c)); }
RV = std::make_unique<if_command>(
std::move(v), std::move(E));
}
%token_class else ELSE_IF ELSE.
%type else_command { if_command::clause_vector_type }
else_command(RV) ::= else(E) sep compound_list(L). {
RV.emplace_back(std::make_unique<if_else_clause>(@E, std::move(L), std::move(E)));
}
else_command(RV) ::= else_command(EC) else(E) sep compound_list(L). {
RV = std::move(EC);
RV.emplace_back(std::make_unique<if_else_clause>(@E, std::move(L), std::move(E)));
}
opt_nl ::= .
opt_nl ::= opt_nl NL .