diff options
Diffstat (limited to 'core/control_flow.nom')
| -rw-r--r-- | core/control_flow.nom | 274 |
1 files changed, 159 insertions, 115 deletions
diff --git a/core/control_flow.nom b/core/control_flow.nom index 03861e3..b2db945 100644 --- a/core/control_flow.nom +++ b/core/control_flow.nom @@ -1,4 +1,4 @@ -#!/usr/bin/env nomsu -V5.12.12.8 +#!/usr/bin/env nomsu -V6.12.12.8 # This file contains compile-time actions that define basic control flow structures like "if" statements and loops. @@ -19,23 +19,25 @@ test: if (no): barf "conditional fail" -(if $condition $if_body) compiles to " +(if $condition $if_body) compiles to (" if \($condition as lua expr) then \($if_body as lua) - end" + end +") test: unless (yes): barf "conditional fail" (unless $condition $unless_body) parses as (if (not $condition) $unless_body) -[if $condition $if_body else $else_body, unless $condition $else_body else $if_body] \ -..all compile to " +[if $condition $if_body else $else_body, unless $condition $else_body else $if_body] +..all compile to (" if \($condition as lua expr) then \($if_body as lua) else \($else_body as lua) - end" + end +") ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -46,29 +48,31 @@ test: assume ((1 if (yes) else 2) == 1) assume ((1 if (no) else 2) == 2) -[..] +[ $when_true_expr if $condition else $when_false_expr $when_true_expr if $condition otherwise $when_false_expr $when_false_expr unless $condition else $when_true_expr $when_false_expr unless $condition then $when_true_expr -..all compile to: +] all compile to: # If %when_true_expr is guaranteed to be truthy, we can use Lua's idiomatic equivalent of a conditional expression: (cond and if_true or if_false) - if {Text, List, Dict, Number}.($when_true_expr.type): - return (Lua "(\($condition as lua expr) and \($when_true_expr as lua expr) or \($when_false_expr as lua expr))") + if {.Text, .List, .Dict, .Number}.($when_true_expr.type): + 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 (..) - Lua " + return + Lua (" ((function() if \($condition as lua expr) then return \($when_true_expr as lua expr) else return \($when_false_expr as lua expr) end - end)())" + end)()) + ") ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -86,17 +90,19 @@ test: go to (Loop) assume ($i == 0) -(--- $label ---) compiles to " - ::label_\(..) - ($label.stub|as lua id) if ($label.type == "Action") else (..) +(--- $label ---) compiles to (" + ::label_\( + ($label.stub, as lua id) if ($label.type == "Action") else $label as lua identifier - ..::" + ):: +") -(go to $label) compiles to " - goto label_\(..) - ($label.stub|as lua id) if ($label.type == "Action") else (..) +(go to $label) compiles to (" + goto label_\( + ($label.stub, as lua id) if ($label.type == "Action") else $label as lua identifier - .." + ) +") # Basic loop control (stop $var) compiles to: @@ -131,8 +137,8 @@ test: (repeat while $condition $body) compiles to: $lua = (Lua "while \($condition as lua expr) do\n \($body as lua)") if ($body has subtree \(do next)): - $lua|add "\n ::continue::" - $lua|add "\nend --while-loop" + $lua, add "\n ::continue::" + $lua, add "\nend --while-loop" return $lua (repeat $body) parses as (repeat while (yes) $body) @@ -143,50 +149,52 @@ test: test: $nums = [] for $x in 1 to 5: - $nums|add $x + $nums, add $x assume ($nums == [1, 2, 3, 4, 5]) $nums = [] for $x in 1 to 5 via 2: - $nums|add $x + $nums, add $x assume ($nums == [1, 3, 5]) $nums = [] for $outer in 1 to 100: for $inner in $outer to ($outer + 2): if ($inner == 2): - $nums|add -2 + $nums, add -2 do next $inner - $nums|add $inner + $nums, add $inner if ($inner == 5): stop $outer assume ($nums == [1, -2, 3, -2, 3, 4, 3, 4, 5]) # Numeric range for loops -[..] +[ for $var in $start to $stop by $step $body for $var in $start to $stop via $step $body -..all compile to: +] all compile to: # This uses Lua's approach of only allowing loop-scoped variables in a loop - $lua = (Lua "for \($var as lua identifier)=\($start as lua expr),\($stop as lua expr),\($step as lua expr) do") - $lua|add "\n " ($body as lua) + $lua = + Lua "for \($var as lua identifier)=\($start as lua expr),\($stop as lua expr),\($step as lua expr) do" + $lua, add "\n " ($body as lua) if ($body has subtree \(do next)): - $lua|add "\n ::continue::" + $lua, add "\n ::continue::" if ($body has subtree \(do next $var)): - $lua|add "\n " (\(---next $var ---) as lua) + $lua, add "\n " (\(---next $var ---) as lua) - $lua|add "\nend -- numeric for " ($var as lua identifier) " loop" + $lua, add "\nend -- numeric for " ($var as lua identifier) " loop" if ($body has subtree \(stop $var)): - $lua = (..) - Lua " + $lua = + Lua (" do -- scope for (stop \($var as lua identifier)) \$lua \(\(---stop $var ---) as lua) - end -- scope for (stop \($var as lua identifier))" + end -- scope for (stop \($var as lua identifier)) + ") return $lua ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -(for $var in $start to $stop $body) parses as (..) +(for $var in $start to $stop $body) parses as for $var in $start to $stop via 1 $body test: @@ -200,7 +208,7 @@ test: $a = [10, 20, 30, 40, 50] $b = [] for $x in $a: - $b|add $x + $b, add $x assume ($a == $b) $b = [] for $x in $a: @@ -210,37 +218,38 @@ test: if ($x == 50): stop $x - $b|add $x + $b, add $x assume ($b == [20, 30, 40]) # For-each loop (lua's "ipairs()") (for $var in $iterable at $i $body) compiles to: # This uses Lua's approach of only allowing loop-scoped variables in a loop - $lua = (..) - Lua " + $lua = + Lua (" for \($i as lua identifier),\($var as lua identifier) in ipairs(\($iterable as lua expr)) do - " - $lua|add ($body as lua) + \; + ") + $lua, add ($body as lua) if ($body has subtree \(do next)): - $lua|add "\n ::continue::" + $lua, add "\n ::continue::" if ($body has subtree \(do next $var)): - $lua|add "\n " (\(---next $var ---) as lua) + $lua, add "\n " (\(---next $var ---) as lua) - $lua|add "\nend --for \($var as lua identifier) loop" + $lua, add "\nend --for \($var as lua identifier) loop" if ($body has subtree \(stop $var)): $inner_lua = $lua $lua = (Lua "do -- scope for stopping for-loop\n ") - $lua|add $inner_lua "\n " - $lua|add (\(---stop $var ---) as lua) - $lua|add "\nend -- end of scope for stopping for-loop" + $lua, add $inner_lua "\n " + $lua, add (\(---stop $var ---) as lua) + $lua, add "\nend -- end of scope for stopping for-loop" return $lua -(for $var in $iterable $body) parses as (..) +(for $var in $iterable $body) parses as for $var in $iterable at (=lua "__") $body test: - $d = {a: 10, b: 20, c: 30, d: 40, e: 50} + $d = {.a = 10, .b = 20, .c = 30, .d = 40, .e = 50} $result = [] for $k = $v in $d: if ($k == "a"): @@ -249,35 +258,36 @@ test: if ($v == 20): do next $v - $result|add "\$k = \$v" + $result, add "\$k = \$v" assume (($result sorted) == ["c = 30", "d = 40", "e = 50"]) # Dict iteration (lua's "pairs()") -[for $key = $value in $iterable $body, for $key $value in $iterable $body] \ +[for $key = $value in $iterable $body, for $key $value in $iterable $body] ..all compile to: - $lua = (Lua "for \($key as lua identifier),\($value as lua identifier) in pairs(\($iterable as lua expr)) do") - $lua|add "\n " ($body as lua) + $lua = + Lua "for \($key as lua identifier),\($value as lua identifier) in pairs(\($iterable as lua expr)) do" + $lua, add "\n " ($body as lua) if ($body has subtree \(do next)): - $lua|add "\n ::continue::" + $lua, add "\n ::continue::" if ($body has subtree \(do next $key)): - $lua|add "\n " (\(---next $key ---) as lua) + $lua, add "\n " (\(---next $key ---) as lua) if ($body has subtree \(do next $value)): - $lua|add "\n " (\(---next $value ---) as lua) + $lua, add "\n " (\(---next $value ---) as lua) - $lua|add "\nend --foreach-loop" + $lua, add "\nend --foreach-loop" $stop_labels = (Lua "") if ($body has subtree \(stop $key)): - $stop_labels|add "\n" (\(---stop $key ---) as lua) + $stop_labels, add "\n" (\(---stop $key ---) as lua) if ($body has subtree \(stop $value)): - $stop_labels|add "\n" (\(---stop $value ---) as lua) + $stop_labels, add "\n" (\(---stop $value ---) as lua) if ((size of "\$stop_labels") > 0): $inner_lua = $lua $lua = (Lua "do -- scope for stopping for % = % loop\n ") - $lua|add $inner_lua $stop_labels "\nend" + $lua, add $inner_lua $stop_labels "\nend" return $lua @@ -303,45 +313,58 @@ test: $clause = "if" $else_allowed = (yes) unless ($body.type is "Block"): - compile error at $body "'if' expected a Block, but got a \($body.type)." \ + compile error at $body "'if' expected a Block, but got a \($body.type)." .."Perhaps you forgot to put a ':' after 'if'?" for $line in $body: - unless (..) - (($line.type is "Action") and ((size of $line) >= 2)) and (..) + unless + (($line.type is "Action") and ((size of $line) >= 2)) and $line.(size of $line) is "Block" syntax tree ..: - compile error at $line "Invalid line for the body of an 'if' block." " - Each line should contain one or more conditional expressions followed by a block, or "else" followed \ - ..by a block." + compile error at $line "Invalid line for the body of an 'if' block." (" + Each line should contain one or more conditional expressions followed by a block, or "else"\ + .. followed by a block. + ") $action = $line.(size of $line) if (($line.1 is "else") and ((size of $line) == 2)): unless $else_allowed: - compile error at $line "You can't have two 'else' blocks." \ + compile error at $line "You can't have two 'else' blocks." .."Merge all of the 'else' blocks together." unless ((size of "\$code") > 0): - compile error at $line \ - .."You can't have an 'else' block without a preceding condition" " - If you want the code in this block to always execute, you don't need a conditional block around it. \ - ..Otherwise, make sure the 'else' block comes last." + compile error at $line + .."You can't have an 'else' block without a preceding condition" (" + If you want the code in this block to always execute, you don't need a conditional block \ + ..around it. Otherwise, make sure the 'else' block comes last. + ") + + $code, add (" + + else + \; + ") ($action as lua) - $code|add "\nelse\n " ($action as lua) $else_allowed = (no) ..else: - $code|add $clause " " + $code, add $clause " " for $i in 1 to ((size of $line) - 1): if ($i > 1): - $code|add " or " - $code|add ($line.$i as lua expr) - $code|add " then\n " ($action as lua) + $code, add " or " + $code, add ($line.$i as lua expr) + + $code, add (" + then + \; + ") ($action as lua) + $clause = "\nelseif" if ((size of "\$code") == 0): - compile error at $body "'if' block has an empty body." \ + compile error at $body "'if' block has an empty body." .."This means nothing would happen, so the 'if' block should be deleted." - $code|add "\nend --when" + $code, add "\nend --when" + return $code test: @@ -365,53 +388,72 @@ test: $else_allowed = (yes) define mangler unless ($body.type is "Block"): - compile error at $body "'if' expected a Block, but got a \($body.type)" \ + compile error at $body "'if' expected a Block, but got a \($body.type)" .."Perhaps you forgot to put a ':' after the 'is'?" for $line in $body: - unless (..) - (($line.type is "Action") and ((size of $line) >= 2)) and (..) + unless + (($line.type is "Action") and ((size of $line) >= 2)) and $line.(size of $line) is "Block" syntax tree ..: - compile error at $line "Invalid line for 'if' block." " - Each line should contain expressions followed by a block, or "else" followed by a block" + compile error at $line "Invalid line for 'if' block." (" + Each line should contain expressions followed by a block, or "else" followed by a block + ") $action = $line.(size of $line) if (($line.1 is "else") and ((size of $line) == 2)): unless $else_allowed: - compile error at $line "You can't have two 'else' blocks." \ + compile error at $line "You can't have two 'else' blocks." .."Merge all of the 'else' blocks together." unless ((size of "\$code") > 0): - compile error at $line \ - .."You can't have an 'else' block without a preceding condition" " - If you want the code in this block to always execute, you don't need a conditional block around it. \ - ..Otherwise, make sure the 'else' block comes last." + compile error at $line + .."You can't have an 'else' block without a preceding condition" (" + If you want the code in this block to always execute, you don't need a conditional block \ + ..around it. Otherwise, make sure the 'else' block comes last. + ") + + $code, add (" + + else + \; + ") ($action as lua) - $code|add "\nelse\n " ($action as lua) $else_allowed = (no) ..else: - $code|add $clause " " + $code, add $clause " " for $i in 1 to ((size of $line) - 1): if ($i > 1): - $code|add " or " - $code|add "\(mangle "branch value") == " ($line.$i as lua expr) - $code|add " then\n " ($action as lua) + $code, add " or " + $code, add "\(mangle "branch value") == " ($line.$i as lua expr) + + $code, add (" + then + \; + ") ($action as lua) + $clause = "\nelseif" if ((size of "\$code") == 0): - compile error at $body "'if' block has an empty body." \ + compile error at $body "'if' block has an empty body." .."This means nothing would happen, so the 'if' block should be deleted." - $code|add "\nend --when" - return (..) - Lua " + $code, add "\nend --when" + + return + Lua (" do --if % is... local \(mangle "branch value") = \($branch_value as lua expr) \$code - end -- if % is..." + end -- if % is... + ") # Do/finally -(do $action) compiles to "do\n \($action as lua)\nend -- do" +(do $action) compiles to (" + do + \($action as lua) + end -- do +") + test: $d = {} try: @@ -424,8 +466,8 @@ test: (do $action then always $final_action) compiles to: define mangler - return (..) - Lua " + return + Lua (" do local \(mangle "fell_through") = false local \(mangle "ok"), \(mangle "ret") = pcall(function() @@ -435,7 +477,8 @@ test: \($final_action as lua) if not \(mangle "ok") then error(ret, 0) end if not \(mangle "fell_through") then return ret end - end" + end + ") test: assume ((result of: return 99) == 99) @@ -450,32 +493,33 @@ test: for $2 in $: recurse $ on $2 ..else: - $flat|add $ + $flat, add $ assume (sorted $flat) == [1, 2, 3, 4, 5, 6] # Recurion control flow (for $var in recursive $structure $body) compiles to: with local compile actions: define mangler - (recurse $v on $x) compiles to (..) + (recurse $v on $x) compiles to Lua "table.insert(\(mangle "stack \($v.1)"), \($x as lua expr))" - $lua = (..) - Lua " + $lua = + Lua (" do local \(mangle "stack \($var.1)") = List{\($structure as lua expr)} while #\(mangle "stack \($var.1)") > 0 do \($var as lua expr) = table.remove(\(mangle "stack \($var.1)"), 1) - \($body as lua)" + \($body as lua) + ") if ($body has subtree \(do next)): - $lua|add "\n ::continue::" + $lua, add "\n ::continue::" if ($body has subtree \(do next $var)): - $lua|add "\n \(\(---next $var ---) as lua)" + $lua, add "\n \(\(---next $var ---) as lua)" - $lua|add "\n end -- Recursive loop" + $lua, add "\n end -- Recursive loop" if ($body has subtree \(stop $var)): - $lua|add "\n \(\(---stop $var ---) as lua)" - $lua|add "\nend -- Recursive scope" + $lua, add "\n \(\(---stop $var ---) as lua)" + $lua, add "\nend -- Recursive scope" return $lua |