Text Format¶

Instructions¶

Control Instructions¶

The label identifier on a structured control instruction may optionally be repeated after the corresponding $end$ , $else$ , $catch$ , $catch_all$ , and $delegate$ pseudo instructions, to indicate the matching delimiters.

\begin{array}{r} \begin{array}{llclll} {blockinstr}_{I} & ::= & \dots \\ | & ‘ try ’ I^{'} : {label}_{I} bt : blocktype ({in}_{1} : {instr}_{I^{'}})^{*} \\ (‘ catch ’ {id}_{1}^{?} x : {tagidx}_{I} ({in}_{2} : {instr}_{I^{'}})^{*})^{*} \\ (‘ catch_all ’ {id}_{1}^{?} ({in}_{3} : {instr}_{I^{'}})^{*})^{?} \\ ‘ end ’ {id}_{2}^{?} \\ \Rightarrow try bt {in}_{1}^{*} (catch x {in}_{2}^{*})^{*} (catch_all {in}_{3}^{*})^{?} end \\ (if {id}_{1}^{?} = ϵ \lor {id}_{1}^{?} = label, {id}_{2}^{?} = ϵ \lor {id}_{2}^{?} = label) \\ | & ‘ try ’ I^{'} : {label}_{I} bt : blocktype ({in}_{1} : {instr}_{I^{'}})^{*} \\ ‘ delegate ’ l : {labelidx}_{I} l : {labelidx}_{I} \\ \Rightarrow try bt {in}_{1}^{*} delegate l (if {id}^{?} = ϵ \lor {id}^{?} = label) \\ {plaininstr}_{I} & ::= & \dots \\ | & ‘ rethrow ’ l : {labelidx}_{I} \Rightarrow rethrow l \end{array} \end{array}