ref: 53fa826a8a695bcfade5c47f636f719c71e96b98
dir: /sys/src/cmd/rc/syn.y/
%term FOR IN WHILE IF NOT TWIDDLE BANG SUBSHELL SWITCH FN %term WORD REDIR DUP PIPE SUB %term SIMPLE ARGLIST WORDS BRACE PAREN PCMD PIPEFD /* not used in syntax */ /* operator priorities -- lowest first */ %left IF WHILE FOR SWITCH ')' NOT %left ANDAND OROR %left BANG SUBSHELL %left PIPE %left '^' %right '$' COUNT '"' %left SUB %{ #include "rc.h" #include "fns.h" %} %union{ struct tree *tree; }; %type<tree> line paren brace body cmdsa cmdsan assign epilog redir %type<tree> cmd simple first word comword keyword words %type<tree> NOT FOR IN WHILE IF TWIDDLE BANG SUBSHELL SWITCH FN %type<tree> WORD REDIR DUP PIPE %% rc: { return 1;} | line '\n' {readhere(lex->input); return !compile($1);} line: cmd | cmdsa line {$$=tree2(';', $1, $2);} body: cmd | cmdsan body {$$=tree2(';', $1, $2);} cmdsa: cmd ';' | cmd '&' {$$=tree1('&', $1);} cmdsan: cmdsa | cmd '\n' {readhere(lex->input);} brace: '{' body '}' {$$=tree1(BRACE, $2);} paren: '(' body ')' {$$=tree1(PCMD, $2);} assign: first '=' word {$$=tree2('=', $1, $3);} epilog: {$$=0;} | redir epilog {$$=mung2($1, $1->child[0], $2);} redir: REDIR word {$$=mung1($1, $2); if($$->rtype==HERE) heredoc($$);} | DUP cmd: {$$=0;} | brace epilog {$$=epimung($1, $2);} | IF paren {skipnl();} cmd {$$=mung2($1, $2, $4);} | IF NOT {skipnl();} cmd {$$=mung1($2, $4);} | FOR '(' word IN words ')' {skipnl();} cmd /* * if ``words'' is nil, we need a tree element to distinguish between * for(i in ) and for(i), the former being a loop over the empty set * and the latter being the implicit argument loop. so if $5 is nil * (the empty set), we represent it as "()". don't parenthesize non-nil * functions, to avoid growing parentheses every time we reread the * definition. */ {$$=mung3($1, $3, $5 ? $5 : tree1(PAREN, $5), $8);} | FOR '(' word ')' {skipnl();} cmd {$$=mung3($1, $3, (tree*)0, $6);} | WHILE paren {skipnl();} cmd {$$=mung2($1, $2, $4);} | SWITCH word {skipnl();} brace {$$=tree2(SWITCH, $2, $4);} | simple {$$=simplemung($1);} | TWIDDLE word words {$$=mung2($1, $2, $3);} | cmd ANDAND cmd {$$=tree2(ANDAND, $1, $3);} | cmd OROR cmd {$$=tree2(OROR, $1, $3);} | cmd PIPE cmd {$$=mung2($2, $1, $3);} | redir cmd %prec BANG {$$=mung2($1, $1->child[0], $2);} | assign cmd %prec BANG {$$=mung3($1, $1->child[0], $1->child[1], $2);} | BANG cmd {$$=mung1($1, $2);} | SUBSHELL cmd {$$=mung1($1, $2);} | FN words brace {$$=tree2(FN, $2, $3);} | FN words {$$=tree1(FN, $2);} simple: first | simple word {$$=globprop(tree2(ARGLIST, $1, $2));} | simple redir {$$=globprop(tree2(ARGLIST, $1, $2));} first: comword | first '^' word {$$=globprop(tree2('^', $1, $3));} word: keyword {lex->lastword=1; $1->type=WORD;} | comword | word '^' word {$$=globprop(tree2('^', $1, $3));} comword: '$' word {$$=tree1('$', $2);} | '$' word SUB words ')' {$$=tree2(SUB, $2, $4);} | '"' word {$$=tree1('"', $2);} | COUNT word {$$=tree1(COUNT, $2);} | WORD | '`' brace {$$=tree2('`', (tree*)0, $2);} | '`' word brace {$$=tree2('`', $2, $3);} | '(' words ')' {$$=globprop(tree1(PAREN, $2));} | REDIR brace {$$=mung1($1, $2); $$->type=PIPEFD;} keyword: FOR|IN|WHILE|IF|NOT|TWIDDLE|BANG|SUBSHELL|SWITCH|FN words: {$$=(tree*)0;} | words word {$$=tree2(WORDS, $1, $2);}