LFTCompiler

Progetto per il Corso di Linguaggi Formali e Traduttori

• Doc del Progetto
• Regole Semantiche

Translator

SDT

• <prog> ::== prog.lnext=newLabel() statlist.lnext=prog.lnext <statlist> emitLabel(prog.lnext) EOF
• <statlist> ::== stat.lnext=newLabel() <stat> emitLabel(stat.lnext) statlistp.lnext=statlist.lnext <statlistp>
• <statlistp> :: ; `stat.lnext=newLabel()` `` `emitLabel(lnext_stat)` `` :: $‘ϵ‘$ goto statlistp.lnext
• <stat> :: = ID `stat.id_addr=st.lookupAddress(ID.lexeme)` `if(stat.id_addr-1) { stat.id_addr=count; st.insert(ID.lexeme,count++) } istore stat.id_addr || goto lnext::== print ()for(n=exprlist.n; n>0; n—) { invokestatic 1 }::== read ( ID )stat.id_addr = &ID.lexeme if(stat.id_addr-1) { stat.id_addr=count; st.insert(ID.lexeme,count++) }` `invokestatic 0 || istore stat.id_addr || goto lnext` :: cond whenlist.else=newLabel() || whenlist.exit=newLabel() <whenlist> emitLabel(whenlist.else) else stat1.lnext=whenlist.exit <stat1> emitLabel(whenlist.exit) goto stat.lnext :: while ( `bexpr.true=newLabel() || bexpr.false=stat.lnext` `emitLabel(bexpr.true)` `` ) `stat1.lnext=stat.lnext` `` :: { || statlist.lnext=stat.lnext || <statlist> }
• <whenlist> ::== whenitem.false = newLabel() <whenitem> goto whenitem.false emitLabel(whenitem.false) ~whenlistp.exit = whenlist.exit <whenlistp> goto whenlist.else
• <whenlistp> :: `whenitem.false = newLabel()` `` `goto whenlistp_exit` `emitLabel(whenitem.false)` `` :: $‘ϵ‘$
• <whenitem> ::== when ( bexpr.true=newLabel() bexpr.false=whenitem.false <bexpr> ) do emitLabel(bexpr.true) stat.lnext=newLabel() <stat> emitLabel(stat.lnext)
• <bexpr> :: RELOP `` `` `if_icmpRELOP bexpr.false` :: true goto bexpr.true :: false `goto bexpr.false` :: ! <bexpr1> goto bexpr1.false :: && ( `bexpr1.true=newLabel() || bexpr1.false=bexpr.false` `` `goto bexpr1.true` `emitLabel(bexpr1.true)` `bexpr2.true=bexpr.true || bexpr2.false=bexpr.false` `` ) :: || ( bexpr1.false=newLabel() || bexpr1.true=bexpr.true <bexpr1> goto bexpr.true emitLabel(bexpr1.false) bexpr2.true=bexpr.true || bexpr2.false=bexpr.false <bexpr2> )
• <exprlist> ::== <expr> <exprlistp> exprlist.n=1+exprlistp.n
• <exprlistp> :: `` `` `exprlistp.n=1+exprlistp1.n` :: $‘ϵ‘$ exprlistp.n=0
• <expr> :: + ( `` ) `for(n=exprlist.n-1; n>0; n--) { iadd }` :: - <expr> <expr> isub :: \* ( `` ) `for(n=exprlist.n-1; n>0; n--) { imul }` :: / <expr> <expr> idiv :: ID `expr.addr=st.lookupAddress(ID.lexeme)` `iload expr.addr` :: NUM ldc NUM.value