diff options
Diffstat (limited to 'core/control_flow.nom')
| -rw-r--r-- | core/control_flow.nom | 234 |
1 files changed, 122 insertions, 112 deletions
diff --git a/core/control_flow.nom b/core/control_flow.nom index ff1a7c1..d96e916 100644 --- a/core/control_flow.nom +++ b/core/control_flow.nom @@ -1,8 +1,8 @@ -#!/usr/bin/env nomsu -V4.8.10 +#!/usr/bin/env nomsu -V4.10.12.7 # This file contains compile-time actions that define basic control flow structures like "if" statements and loops. - + use "core/metaprogramming.nom" use "core/operators.nom" use "core/errors.nom" @@ -10,13 +10,15 @@ use "core/errors.nom" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # No-Op -test: do nothing +test: + do nothing (do nothing) compiles to "" # Conditionals test: if (no): barf "conditional fail" + (if %condition %if_body) compiles to "\ ..if \(%condition as lua expr) then \(%if_body as lua) @@ -25,9 +27,9 @@ test: 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 +[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) @@ -43,6 +45,7 @@ test: 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 @@ -51,12 +54,8 @@ test: ..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:yes, List:yes, Dict:yes, Number:yes}.(%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: yes, List: yes, Dict: yes, Number: yes}.(%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!) @@ -78,35 +77,37 @@ test: %i = 0 === %loop === %i += 1 - unless (%i == 10): go to %loop + unless (%i == 10): + go to %loop assume (%i == 10) === (Loop) === %i -= 1 - unless (%i == 0): go to (Loop) + unless (%i == 0): + go to (Loop) assume (%i == 0) + [=== %label ===, --- %label ---, *** %label ***] all compile to "\ - ..::label_\(..) - (%label.stub if (%label.type == "Action") else %label) as lua identifier - ..::" + ..::label_\((%label.stub if (%label.type == "Action") else %label) as lua identifier)::" (go to %label) compiles to "\ - ..goto label_\(..) - (%label.stub if (%label.type == "Action") else %label) as lua identifier - .." + ..goto label_\((%label.stub if (%label.type == "Action") else %label) as lua identifier)" # Basic loop control (stop %var) compiles to: if %var: - return (..) - Lua "goto stop_\((%var.stub if (%var.type == "action") else %var) as lua identifier)" - ..else: return (Lua "break") + return (Lua "goto stop_\((%var.stub if (%var.type == "action") else %var) as lua identifier)") + ..else: + return (Lua "break") + (do next %var) compiles to: if %var: - return (..) - Lua "goto continue_\((%var.stub if (%var.type == "action") else %var) as lua identifier)" - ..else: return (Lua "goto continue") + return (Lua "goto continue_\((%var.stub if (%var.type == "action") else %var) as lua identifier)") + ..else: + return (Lua "goto continue") + [===stop %var ===, ---stop %var ---, ***stop %var ***] all compile to "\ ..::stop_\((%var.stub if (%var.type == "action") else %var) as lua identifier)::" + [===next %var ===, ---next %var ---, ***next %var ***] all compile to "\ ..::continue_\((%var.stub if (%var.type == "action") else %var) as lua identifier)::" @@ -116,32 +117,31 @@ test: repeat while (%x < 10): %x += 1 assume (%x == 10) repeat while (%x < 20): stop - repeat while (%x < 20): stop repeating + repeat while (%x < 20): + stop repeating assume (%x == 10) repeat while (%x < 20): %x += 1 - if (yes): do next + if (yes): + do next barf "Failed to 'do next'" - assume (%x == 20) repeat while (%x < 30): %x += 1 - if (yes): do next repeat + if (yes): + do next repeat barf "Failed to 'do next repeat'" - assume (%x == 30) (do next repeat) compiles to "goto continue_repeat" (stop repeating) compiles to "goto stop_repeat" (repeat while %condition %body) compiles to: - %lua = (..) - Lua "\ - ..while \(%condition as lua expr) do - \(%body as lua)" - + %lua = (Lua "while \(%condition as lua expr) do\n \(%body as lua)") if (%body has subtree \(do next)): %lua::append "\n ::continue::" + if (%body has subtree \(do next repeat)): %lua::append "\n ::continue_repeat::" + %lua::append "\nend --while-loop" if (%body has subtree \(stop repeating)): %inner_lua = %lua @@ -150,25 +150,24 @@ test: .. ::stop_repeat:: end -- end of 'stop repeating' label scope" - return %lua - (repeat %body) parses as (repeat while (yes) %body) (repeat until %condition %body) parses as (repeat while (not %condition) %body) - test: %x = 0 repeat 10 times: %x += 1 assume (%x == 10) + (repeat %n times %body) compiles to: define mangler - %lua = (..) - Lua "for \(mangle "i")=1,\(%n as lua expr) do\n " + %lua = (Lua "for \(mangle "i")=1,\(%n as lua expr) do\n ") %lua::append (%body as lua) if (%body has subtree \(do next)): %lua::append "\n ::continue::" + if (%body has subtree \(do next repeat)): %lua::append "\n ::continue_repeat::" + %lua::append "\nend --numeric for-loop" if (%body has subtree \(stop repeating)): %inner_lua = %lua @@ -177,17 +176,18 @@ test: .. ::stop_repeat:: end -- end of 'stop repeating' label scope" - return %lua ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ test: %nums = [] - for %x in 1 to 5: %nums::add %x + for %x in 1 to 5: + %nums::add %x assume (%nums == [1, 2, 3, 4, 5]) %nums = [] - for %x in 1 to 5 via 2: %nums::add %x + for %x in 1 to 5 via 2: + %nums::add %x assume (%nums == [1, 3, 5]) %nums = [] for %outer in 1 to 100: @@ -195,10 +195,9 @@ test: if (%inner == 2): %nums::add -2 do next %inner - %nums::add %inner - if (%inner == 5): stop %outer - + if (%inner == 5): + stop %outer assume (%nums == [1, -2, 3, -2, 3, 4, 3, 4, 5]) # Numeric range for loops @@ -209,15 +208,11 @@ test: # This uses Lua's approach of only allowing loop-scoped variables in a loop unless (%var.type is "Var"): compile error at %var "Expected a variable here, not a \(%var.type)" - %lua = (..) - Lua "\ - ..for \(%var as lua expr)=\(%start as lua expr),\(%stop as lua expr),\(..) - %step as lua expr - .. do" - + %lua = (Lua "for \(%var as lua expr)=\(%start as lua expr),\(%stop as lua expr),\(%step as lua expr) do") %lua::append "\n " (%body as lua) if (%body has subtree \(do next)): %lua::append "\n ::continue::" + if (%body has subtree \(do next %var)): %lua::append "\n " (what (===next %var ===) compiles to) @@ -228,7 +223,6 @@ test: %lua::append %inner_lua "\n " %lua::append (what (===stop %var ===) compiles to) %lua::append "\nend -- end of scope for stopping for-loop" - return %lua ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -239,25 +233,33 @@ test: test: %a = [10, 20, 30, 40, 50] %b = [] - for %x in %a: %b::add %x + for %x in %a: + %b::add %x assume (%a == %b) %b = [] for %x in %a: - if (%x == 10): do next %x - if (%x == 50): stop %x + if (%x == 10): + do next %x + + if (%x == 50): + stop %x + %b::add %x - assume (%b == [20, 30, 40]) # For-each loop (lua's "ipairs()") (for %var in %iterable %body) compiles to: define mangler + # This uses Lua's approach of only allowing loop-scoped variables in a loop %lua = (..) - Lua "for \(mangle "i"),\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do\n " + Lua "\ + ..for \(mangle "i"),\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do + " %lua::append (%body as lua) if (%body has subtree \(do next)): %lua::append "\n ::continue::" + if (%body has subtree \(do next %var)): %lua::append "\n " (what (===next %var ===) compiles to) @@ -268,17 +270,19 @@ test: %lua::append %inner_lua "\n " %lua::append (what (===stop %var ===) compiles to) %lua::append "\nend -- end of scope for stopping for-loop" - return %lua # TODO: reduce code duplication (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 "for \(%i as lua identifier),\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do\n " + Lua "\ + ..for \(%i as lua identifier),\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do + " %lua::append (%body as lua) if (%body has subtree \(do next)): %lua::append "\n ::continue::" + if (%body has subtree \(do next %var)): %lua::append "\n " (what (===next %var ===) compiles to) @@ -289,37 +293,36 @@ test: %lua::append %inner_lua "\n " %lua::append (what (===stop %var ===) compiles to) %lua::append "\nend -- end of scope for stopping for-loop" - return %lua 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"): do next %k - if (%v == 20): do next %v + if (%k == "a"): + do next %k + + if (%v == 20): + do next %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: # This uses Lua's approach of only allowing loop-scoped variables in a loop unless (%key.type is "Var"): compile error at %key "Expected a variable here, not a \(%key.type)" + unless (%value.type is "Var"): compile error at %value "Expected a variable here, not a \(%value.type)" - %lua = (..) - Lua "\ - ..for \(%key as lua identifier),\(%value as lua identifier) in pairs(\(..) - %iterable as lua expr - ..) do" + %lua = (Lua "for \(%key as lua identifier),\(%value as lua identifier) in pairs(\(%iterable as lua expr)) do") %lua::append "\n " (%body as lua) if (%body has subtree \(do next)): %lua::append "\n ::continue::" + if (%body has subtree \(do next %key)): %lua::append "\n " (what (===next %key ===) compiles to) @@ -350,8 +353,10 @@ test: (1 == 0) (1 == 1) %not_a_variable.x: do nothing (1 == 1): barf "bad conditional" + (1 == 2): barf "bad conditional" + else: barf "bad conditional" @@ -361,30 +366,29 @@ test: %clause = "if" %else_allowed = (yes) unless (%body.type is "Block"): - compile error at %body "'if' expected a Block, but got a \(%body.type)." - ..hint "Perhaps you forgot to put a ':' after 'if'?" + 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 (..) %line.(size of %line) is "Block" syntax tree ..: - compile error at %line "Invalid line for the body of an 'if' block." - ..hint "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." - ..hint "Merge all of the 'else' blocks together." + 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 preceeding condition" - ..hint "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." + .."\ + ..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::append "\nelse\n " (%action as lua) %else_allowed = (no) @@ -394,13 +398,13 @@ test: if (%i > 1): %code::append " or " %code::append (%line.%i as lua expr) - %code::append " then\n " (%action as lua) %clause = "\nelseif" if ((size of "\%code") == 0): - compile error at %body "'if' block has an empty body." - ..hint "This means nothing would happen, so the 'if' block should be deleted." + compile error at %body "'if' block has an empty body." "\ + ..This means nothing would happen, so the 'if' block should be deleted." + %code::append "\nend --when" return %code @@ -408,9 +412,13 @@ test: if 5 is: 1 2 3: barf "bad switch statement" - 4 5: do nothing + + 4 5: + do nothing + 5 6: barf "bad switch statement" + else: barf "bad switch statement" @@ -421,28 +429,28 @@ test: %else_allowed = (yes) define mangler unless (%body.type is "Block"): - compile error at %body "'if' expected a Block, but got a \(%body.type)" - ..hint "Perhaps you forgot to put a ':' after the 'is'?" + 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 (..) %line.(size of %line) is "Block" syntax tree ..: - compile error at %line "Invalid line for 'if' block." - ..hint "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." - ..hint "Merge all of the 'else' blocks together." + 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 preceeding condition" - ..hint "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." + .."\ + ..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::append "\nelse\n " (%action as lua) %else_allowed = (no) @@ -452,13 +460,13 @@ test: if (%i > 1): %code::append " or " %code::append "\(mangle "branch value") == " (%line.%i as lua expr) - %code::append " then\n " (%action as lua) %clause = "\nelseif" if ((size of "\%code") == 0): - compile error at %body "'if' block has an empty body." - ..hint "This means nothing would happen, so the 'if' block should be deleted." + compile error at %body "'if' block has an empty body." "\ + ..This means nothing would happen, so the 'if' block should be deleted." + %code::append "\nend --when" return (..) Lua "\ @@ -468,19 +476,17 @@ test: end -- if % is..." # Do/finally -(do %action) compiles to "\ - ..do - \(%action as lua) - end -- do" - +(do %action) compiles to "do\n \(%action as lua)\nend -- do" test: %d = {} try: do: %d.x = "bad" barf - ..then always: %d.x = "good" + ..then always: + %d.x = "good" assume (%d.x == "good") + (do %action then always %final_action) compiles to: define mangler return (..) @@ -497,19 +503,19 @@ test: end" test: - assume ((result of (: return 99)) == 99) + assume ((result of: return 99) == 99) # Inline thunk: (result of %body) compiles to "\(what ([] -> %body) compiles to)()" - test: %t = [1, [2, [[3], 4], 5, [[[6]]]]] %flat = [] for % in recursive %t: if ((lua type of %) is "table"): - for %2 in %: recurse % on %2 - ..else: %flat::add % - + for %2 in %: + recurse % on %2 + ..else: + %flat::add % assume (sorted %flat) == [1, 2, 3, 4, 5, 6] # Recurion control flow @@ -518,6 +524,7 @@ test: define mangler (recurse %v on %x) compiles to (..) Lua "table.insert(\(mangle "stack \(%v.1)"), \(%x as lua expr))" + %lua = (..) Lua "\ ..do @@ -525,10 +532,13 @@ test: while #\(mangle "stack \(%var.1)") > 0 do \(%var as lua expr) = table.remove(\(mangle "stack \(%var.1)"), 1) \(%body as lua)" + if (%body has subtree \(do next)): %lua::append "\n ::continue::" + if (%body has subtree \(do next %var)): %lua::append "\n \(what (===next %var ===) compiles to)" + %lua::append "\n end -- Recursive loop" if (%body has subtree \(stop %var)): %lua::append "\n \(what (===stop %var ===) compiles to)" |