diff options
Diffstat (limited to 'core/control_flow.nom')
| -rw-r--r-- | core/control_flow.nom | 192 |
1 files changed, 82 insertions, 110 deletions
diff --git a/core/control_flow.nom b/core/control_flow.nom index 3f6c59c..5a3a775 100644 --- a/core/control_flow.nom +++ b/core/control_flow.nom @@ -13,30 +13,19 @@ immediately: # Conditionals immediately: compile [if %condition %if_body] to: - %if_body <- (%if_body as lua) - return {..} - locals: %if_body.locals - statements:".." - if \(%condition as lua expr) then - \(%if_body.statements or "\(%if_body.expr);") - end + Lua ".." + if \(%condition as lua expr) then + \(%if_body as lua statements) + end parse [unless %condition %unless_body] as: if (not %condition) %unless_body compile [if %condition %if_body else %else_body, unless %condition %else_body else %if_body] to: - %if_body <- (%if_body as lua) - %else_body <- (%else_body as lua) - lua> ".." - local \%locals = {unpack(\%if_body.locals or {})}; - for i,loc in ipairs(\%else_body.locals or {}) do table.insert(\%locals, loc); end - utils.deduplicate(\%locals); - return {..} - locals:%locals - statements:".." - if \(%condition as lua expr) then - \(%if_body.statements or "\(%if_body.expr);") - else - \(%else_body.statements or "\(%else_body.expr);") - end + Lua ".." + if \(%condition as lua expr) then + \(%if_body as lua statements) + else + \(%else_body as lua statements) + end # Conditional expression (ternary operator) #.. Note: this uses a function instead of "(condition and if_expr or else_expr)" @@ -51,14 +40,15 @@ immediately #.. If %when_true_expr is guaranteed to be truthy, we can use Lua's idiomatic equivalent of a conditional expression: (cond and if_true or if_false) if: %when_true_expr.type in {Text:yes, List:yes, Dict:yes, Number:yes} - return {..} - expr:"(\(%condition as lua expr) and \(%when_true_expr as lua expr) or \(%when_false_expr as lua expr))" + return: + Lua ".." + (\(%condition as lua expr) and \(%when_true_expr as lua expr) or \(%when_false_expr as lua expr)) ..else: #.. Otherwise, need to do an anonymous inline function (yuck, too bad lua doesn't have a proper ternary operator!) To see why this is necessary consider: (random()<.5 and false or 99) - return {..} - expr: ".." + return: + Lua ".." (function() if \(%condition as lua expr) then return \(%when_true_expr as lua expr); @@ -82,67 +72,59 @@ immediately: # Helper function immediately: compile [if %tree has subtree %subtree where %condition %body] to: - %body_lua <- (%body as lua) - %body_statements <- (%body_lua.statements or "\(%body_lua.expr);") - return {..} - locals: %body_lua.locals - statements:".." - for \(%subtree as lua expr) in coroutine.wrap(function() nomsu:walk_tree(\(%tree as lua expr)) end) do - if Types.is_node(\(%subtree as lua expr)) then - if \(%condition as lua expr) then - \%body_statements - break; - end + Lua ".." + for \(%subtree as lua expr) in coroutine.wrap(function() nomsu:walk_tree(\(%tree as lua expr)) end) do + if Types.is_node(\(%subtree as lua expr)) then + if \(%condition as lua expr) then + \(%body as lua statements) + break; end end + end # While loops immediately: compile [do next repeat] to {statements:"goto continue_repeat;"} compile [stop repeating] to {statements:"goto stop_repeat;"} compile [repeat while %condition %body] to - %body_lua <- (%body as lua) - %body_statements <- (%body_lua.statements or "\(%body_lua.expr);") + %lua <-: Lua "while \(%condition as lua expr) do" if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "do next repeat") - ..: %body_statments +<- "\n::continue_repeat::;" - %code <- ".." - while \(%condition as lua expr) do - \%body_statements - end --while-loop + ..: + %lua +<- "\n::continue_repeat::;" + %lua +<- "\n" + %lua +<- (%body as lua statements) + %lua +<- "\nend --while-loop" if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "stop repeating") ..: - %code <- ".." + %lua <- ".." do -- scope of "stop repeating" label - \%code + \%lua ::stop_repeat::; end -- end of "stop repeating" label scope - return {statements:%code, locals:%body_lua.locals} + return %lua parse [repeat %body] as: repeat while (yes) %body parse [repeat until %condition %body] as: repeat while (not %condition) %body compile [..] repeat %n times %body ..to: - %body_lua <- (%body as lua) - %body_statements <- (%body_lua.statements or "\(%body_lua.expr);") + %lua <-: Lua "for i=1,\(%n as lua expr) do" if %body has subtree % where (%.type = "FunctionCall") and ((%'s stub) is "do next repeat") - ..: %body_statements +<- "\n::continue_repeat::;" - %code <- ".." - for i=1,\(%n as lua expr) do - \%body_statements - end --numeric for-loop + ..: %lua +<- "\n::continue_repeat::;" + %lua +<- "\n\(%body as lua statements)\nend --numeric for-loop" if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "stop repeating") ..: - %code <- ".." - do -- scope of "stop repeating" label - \%code - ::stop_repeat::; - end -- end of "stop repeating" label scope - return {statements:%code, locals:%body_lua.locals} + %lua <-: + Lua ".." + do -- scope of "stop repeating" label + \%lua + ::stop_repeat::; + end -- end of "stop repeating" label scope + return %lua # For loop control flow: immediately: @@ -157,33 +139,30 @@ immediately: for %var from %start to %stop by %step %body for %var from %start to %stop via %step %body ..to: - %body_lua <- (%body as lua) - %body_statements <- (%body_lua.statements or "\(%body_lua.expr);") + # This uses Lua's approach of only allowing loop-scoped variables in a loop + assume (%var.type is "Var") or barf "Loop expected variable, not: \(%var's source code)" + %lua <- + Lua ".." + for \(%var as lua expr)=\(%start as lua expr),\(%n as lua expr) do if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "do next %") and %.value.3.value is %var.value - ..: %body_statements +<- "\n::continue_\(%var as lua identifier)::;" - - # This uses Lua's approach of only allowing loop-scoped variables in a loop - assume (%var.type is "Var") or barf "Loop expected variable, not: \(%var's source code)" - %code <- ".." - for \(%var as lua expr)=\(%start as lua expr),\(%stop as lua expr),\(%step as lua expr) do - \%body_statements - end --numeric for-loop + ..: %lua write code "\n::continue_\(%var as lua identifier)::;" + %lua write code "\n\(%body as lua statements)\nend --numeric for-loop" if %body has subtree % where: (%.type = "FunctionCall") and: ((%'s stub) is "stop %") and: %.value.2.value is %var.value ..: - %code <- ".." + %lua write code ".." do -- scope for stopping for-loop - \%code + \%lua ::stop_\(%var as lua identifier)::; end -- end of scope for stopping for-loop - return {statements:%code, locals:%body_lua.locals} + return %lua immediately: parse [for %var from %start to %stop %body] as: for %var from %start to %stop via 1 %body @@ -196,57 +175,49 @@ immediately: # For-each loop (lua's "ipairs()") immediately: compile [for %var in %iterable %body] to: - %body_lua <- (%body as lua) - %body_statements <- (%body_lua.statements or "\(%body_lua.expr);") + # This uses Lua's approach of only allowing loop-scoped variables in a loop + assume (%var.type is "Var") or barf "Loop expected variable, not: \(%var's source code)" + %lua <-: Lua "for i,\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do" if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "do next %") and %.value.3.value is %var.value - ..: %body_statements +<- "\n::continue_\(%var as lua identifier)::;" - # This uses Lua's approach of only allowing loop-scoped variables in a loop - assume (%var.type is "Var") or barf "Loop expected variable, not: \(%var's source code)" - %code <- ".." - for i,\(%var as lua expr) in ipairs(\(%iterable as lua expr)) do - \%body_statements - end --foreach-loop + ..: %lua +<- (Lua "\n::continue_\(%var as lua identifier)::;") + %lua +<- (Lua "\n\(%body as lua statements)\nend --foreach-loop") if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "stop %") and %.value.2.value is %var.value ..: - %code <- ".." - do -- scope for stopping for-loop - \%code - ::stop_\(%var as lua identifier)::; - end -- end of scope for stopping for-loop - return {statements:%code, locals:%body_lua.locals} + %lua <- + Lua ".." + do -- scope for stopping for-loop + \%lua + ::stop_\(%var as lua identifier)::; + end -- end of scope for stopping for-loop + return %lua parse [for all %iterable %body] as: for % in %iterable %body # Dict iteration (lua's "pairs()") immediately: compile [for %key = %value in %iterable %body] to: - %body_lua <- (%body as lua) - %body_statements <- (%body_lua.statements or "\(%body_lua.expr);") + # This uses Lua's approach of only allowing loop-scoped variables in a loop + assume (%key.type is "Var") or barf "Loop expected variable, not: \(%key's source code)" + assume (%value.type is "Var") or barf "Loop expected variable, not: \(%value's source code)" + %lua <- (Lua "for \(%key as lua identifier),\(%value as lua identifier) in pairs(\(%iterable as lua expr)) do") if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "do next %") and %.value.3.value is %key.value - ..: %body_statements +<- "\n::continue_\(%key as lua identifier)::;" + ..: %lua +<- (Lua "\n::continue_\(%key as lua identifier)::;") if %body has subtree % where: (%.type = "FunctionCall") and ((%'s stub) is "do next %") and %.value.3.value is %value.value - ..: %body_statements +<- "\n::continue_\(%value as lua identifier)::;" - - # This uses Lua's approach of only allowing loop-scoped variables in a loop - assume (%key.type is "Var") or barf "Loop expected variable, not: \(%key's source code)" - assume (%value.type is "Var") or barf "Loop expected variable, not: \(%value's source code)" - %code <- ".." - for \(%key as lua expr),\(%value as lua expr) in pairs(\(%iterable as lua expr)) do - \%body_statements - end --foreach-loop + ..: %lua +<- (Lua "\n::continue_\(%value as lua identifier)::;") + %lua +<- (Lua "\n\(%body as lua statements)\nend --foreach-loop") %stop_labels <- "" if %body has subtree % where: @@ -262,11 +233,12 @@ immediately: ..: %stop_labels +<- "\n::stop_\(%value as lua identifier)::;" if: %stop_labels is not "" - %code <- ".." - do -- scope for stopping for % = % loop - \%code\%stop_labels - end - return {statements:%code, locals:%body_lua.locals} + %lua <- + Lua ".." + do -- scope for stopping for % = % loop + \%lua\%stop_labels + end + return %lua # Switch statement/multi-branch if immediately: @@ -279,11 +251,11 @@ immediately: for %func_call in %body.value: assume (%func_call.type is "FunctionCall") or barf ".." Invalid format for 'when' statement. Only '*' blocks are allowed. - with [..] - %tokens <- %func_call.value - %star <- (1st in %tokens) - %condition <- (2nd in %tokens) - %action <- (3rd in %tokens) + with {..} + %tokens: %func_call.value + %star: %tokens.1 + %condition: %tokens.2 + %action: %tokens.3 ..: assume (=lua "\%star and \%star.type == 'Word' and \%star.value == '*'") or barf ".." Invalid format for 'when' statement. Lines must begin with '*' @@ -334,7 +306,7 @@ immediately: assume (%func_call.type is "FunctionCall") or barf ".." Invalid format for 'when' statement. Only '*' blocks are allowed. %tokens <- %func_call.value - with [%star<-(1st in %tokens), %condition<-(2nd in %tokens), %action<-(3rd in %tokens)]: + with {%star:%tokens.1, %condition:%tokens.2, %action:%tokens.3}: assume (=lua "\%star and \%star.type == 'Word' and \%star.value == '*'") or barf ".." Invalid format for 'when' statement. Lines must begin with '*' assume %condition or barf ".." |