520 lines
17 KiB
Plaintext
520 lines
17 KiB
Plaintext
#!/usr/bin/env nomsu -V2.5.4.3
|
|
#
|
|
This file contains compile-time actions that define basic control flow structures
|
|
like "if" statements and loops.
|
|
|
|
use "core/metaprogramming.nom"
|
|
use "core/text.nom"
|
|
use "core/operators.nom"
|
|
use "core/errors.nom"
|
|
|
|
# No-Op
|
|
test: do nothing
|
|
compile [do nothing] to (Lua "")
|
|
|
|
# Conditionals
|
|
test:
|
|
if (no):
|
|
barf "conditional fail"
|
|
|
|
compile [if %condition %if_body] to (..)
|
|
Lua ".."
|
|
if \(%condition as lua expr) then
|
|
\(%if_body as lua statements)
|
|
end
|
|
|
|
test:
|
|
unless (yes):
|
|
barf "conditional fail"
|
|
|
|
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 (..)
|
|
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)"
|
|
because that breaks if %if_expr is falsey, e.g. "x < 5 and false or 99"
|
|
test:
|
|
assume ((1 if (yes) else 2) == 1)
|
|
assume ((1 if (no) else 2) == 2)
|
|
|
|
compile [..]
|
|
%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
|
|
..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 value ".."
|
|
(\(%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 value ".."
|
|
((function()
|
|
if \(%condition as lua expr) then
|
|
return \(%when_true_expr as lua expr)
|
|
else
|
|
return \(%when_false_expr as lua expr)
|
|
end
|
|
end)())
|
|
|
|
# GOTOs
|
|
test:
|
|
%i = 0
|
|
=== %loop ===
|
|
%i += 1
|
|
unless (%i == 10): go to %loop
|
|
assume (%i == 10)
|
|
|
|
compile [=== %label ===, --- %label ---, *** %label ***] to (..)
|
|
Lua "::label_\(%label as lua identifier)::"
|
|
|
|
compile [go to %label] to (Lua "goto label_\(%label as lua identifier)")
|
|
|
|
# Basic loop control
|
|
compile [do next] to (Lua "goto continue")
|
|
compile [stop] to (Lua "break")
|
|
|
|
# While loops
|
|
test:
|
|
%x = 0
|
|
repeat while (%x < 10): %x += 1
|
|
assume (%x == 10)
|
|
repeat while (%x < 20): stop
|
|
repeat while (%x < 20): stop repeating
|
|
assume (%x == 10)
|
|
repeat while (%x < 20):
|
|
%x += 1
|
|
if (yes): do next
|
|
barf "Failed to 'do next'"
|
|
|
|
assume (%x == 20)
|
|
repeat while (%x < 30):
|
|
%x += 1
|
|
if (yes): do next repeat
|
|
barf "Failed to 'do next repeat'"
|
|
|
|
assume (%x == 30)
|
|
|
|
compile [do next repeat] to (Lua "goto continue_repeat")
|
|
compile [stop repeating] to (Lua "goto stop_repeat")
|
|
compile [repeat while %condition %body] to:
|
|
%lua = (..)
|
|
Lua ".."
|
|
while \(%condition as lua expr) do
|
|
\(%body as lua statements)
|
|
|
|
if (%body has subtree \(do next)):
|
|
to %lua write "\n ::continue::"
|
|
if (%body has subtree \(do next repeat)):
|
|
to %lua write "\n ::continue_repeat::"
|
|
to %lua write "\nend --while-loop"
|
|
if (%body has subtree \(stop repeating)):
|
|
%lua = (..)
|
|
Lua ".."
|
|
do -- scope of "stop repeating" label
|
|
\%lua
|
|
::stop_repeat::
|
|
end -- end of "stop repeating" label scope
|
|
|
|
return %lua
|
|
|
|
parse [repeat %body] as (repeat while (yes) %body)
|
|
parse [repeat until %condition %body] as (repeat while (not %condition) %body)
|
|
test:
|
|
%x = 0
|
|
repeat 10 times: %x += 1
|
|
assume (%x == 10)
|
|
|
|
compile [repeat %n times %body] to:
|
|
%lua = (..)
|
|
Lua ".."
|
|
for i=1,\(%n as lua expr) do
|
|
\(%body as lua statements)
|
|
|
|
if (%body has subtree \(do next)):
|
|
to %lua write "\n ::continue::"
|
|
if (%body has subtree \(do next repeat)):
|
|
to %lua write "\n ::continue_repeat::"
|
|
to %lua write "\nend --numeric for-loop"
|
|
if (%body has subtree \(stop repeating)):
|
|
%lua = (..)
|
|
Lua ".."
|
|
do -- scope of "stop repeating" label
|
|
\%lua
|
|
::stop_repeat::
|
|
end -- end of "stop repeating" label scope
|
|
|
|
return %lua
|
|
|
|
# For loop control flow
|
|
compile [stop %var] to (Lua "goto stop_\(%var as lua identifier)")
|
|
compile [do next %var] to (Lua "goto continue_\(%var as lua identifier)")
|
|
compile [===stop %var ===, ---stop %var ---, ***stop %var ***] to (..)
|
|
Lua "::stop_\(%var as lua identifier)::"
|
|
|
|
compile [===next %var ===, ---next %var ---, ***next %var ***] to (..)
|
|
Lua "::continue_\(%var as lua identifier)::"
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
test:
|
|
%nums = []
|
|
for %x in 1 to 5: add %x to %nums
|
|
assume (%nums == [1, 2, 3, 4, 5])
|
|
%nums = []
|
|
for %x in 1 to 5 via 2: add %x to %nums
|
|
assume (%nums == [1, 3, 5])
|
|
%nums = []
|
|
for %outer in 1 to 100:
|
|
for %inner in %outer to (%outer + 2):
|
|
if (%inner == 2):
|
|
add -2 to %nums
|
|
do next %inner
|
|
|
|
add %inner to %nums
|
|
if (%inner == 5): stop %outer
|
|
|
|
assume (%nums == [1, -2, 3, -2, 3, 4, 3, 4, 5])
|
|
|
|
# Numeric range for loops
|
|
compile [..]
|
|
for %var in %start to %stop by %step %body
|
|
for %var in %start to %stop via %step %body
|
|
..to:
|
|
# This uses Lua's approach of only allowing loop-scoped variables in a loop
|
|
unless (%var.type is "Var"):
|
|
compile error at %var.source "Loop expected variable, not: %s"
|
|
%lua = (..)
|
|
Lua ".."
|
|
for \(%var as lua expr)=\(%start as lua expr),\(%stop as lua expr),\(..)
|
|
%step as lua expr
|
|
.. do
|
|
\(%body as lua statements)
|
|
|
|
if (%body has subtree \(do next)):
|
|
to %lua write "\n ::continue::"
|
|
if (%body has subtree (\(do next %v) with vars {v:%var})):
|
|
to %lua write "\n \(compile as (===next %var ===))"
|
|
to %lua write "\nend --numeric for-loop"
|
|
if (%body has subtree (\(stop %v) with vars {v:%var})):
|
|
%lua = (..)
|
|
Lua ".."
|
|
do -- scope for stopping for-loop
|
|
\%lua
|
|
\(compile as (===stop %var ===))
|
|
end -- end of scope for stopping for-loop
|
|
|
|
return %lua
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
parse [for %var in %start to %stop %body] as (..)
|
|
for %var in %start to %stop via 1 %body
|
|
|
|
test:
|
|
%a = [10, 20, 30, 40, 50]
|
|
%b = []
|
|
for %x in %a: add %x to %b
|
|
assume (%a == %b)
|
|
%b = []
|
|
for %x in %a:
|
|
if (%x == 10): do next %x
|
|
if (%x == 50): stop %x
|
|
add %x to %b
|
|
|
|
assume (%b == [20, 30, 40])
|
|
|
|
# For-each loop (lua's "ipairs()")
|
|
compile [for %var in %iterable %body] to:
|
|
# This uses Lua's approach of only allowing loop-scoped variables in a loop
|
|
unless (%var.type is "Var"):
|
|
compile error at %var.source "Loop expected variable, not: %s"
|
|
%lua = (..)
|
|
Lua ".."
|
|
for i,\(%var as lua identifier) in ipairs(\(%iterable as lua expr)) do
|
|
\(%body as lua statements)
|
|
|
|
if (%body has subtree \(do next)):
|
|
to %lua write "\n ::continue::"
|
|
if (%body has subtree (\(do next %v) with vars {v:%var})):
|
|
to %lua write (Lua "\n\(compile as (===next %var ===))")
|
|
to %lua write "\nend --foreach-loop"
|
|
if (%body has subtree (\(stop %v) with vars {v:%var})):
|
|
%lua = (..)
|
|
Lua ".."
|
|
do -- scope for stopping for-loop
|
|
\%lua
|
|
\(compile as (===stop %var ===))
|
|
end -- end of scope for stopping for-loop
|
|
|
|
return %lua
|
|
|
|
test:
|
|
%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
|
|
add "\%k = \%v" to %result
|
|
|
|
assume ((%result sorted) == ["c = 30", "d = 40", "e = 50"])
|
|
|
|
# Dict iteration (lua's "pairs()")
|
|
compile [..]
|
|
for %key = %value in %iterable %body, for %key %value in %iterable %body
|
|
..to:
|
|
# This uses Lua's approach of only allowing loop-scoped variables in a loop
|
|
unless (%key.type is "Var"):
|
|
compile error at %key.source "Loop expected variable, not: %s"
|
|
unless (%value.type is "Var"):
|
|
compile error at %value.source "Loop expected variable, not: %s"
|
|
%lua = (..)
|
|
Lua ".."
|
|
for \(%key as lua identifier),\(%value as lua identifier) in pairs(\(..)
|
|
%iterable as lua expr
|
|
..) do
|
|
\(%body as lua statements)
|
|
|
|
if (%body has subtree \(do next)):
|
|
to %lua write "\n ::continue::"
|
|
if (%body has subtree (\(do next %v) with vars {v:%key})):
|
|
to %lua write (Lua "\n\(compile as (===next %key ===))")
|
|
if (%body has subtree (\(do next %v) with vars {v:%value})):
|
|
to %lua write (Lua "\n\(compile as (===next %value ===))")
|
|
to %lua write "\nend --foreach-loop"
|
|
%stop_labels = (Lua "")
|
|
if (%body has subtree (\(stop %v) with vars {v:%key})):
|
|
to %stop_labels write "\n\(compile as (===stop %key ===))"
|
|
if (%body has subtree (\(stop %v) with vars {v:%value})):
|
|
to %stop_labels write "\n\(compile as (===stop %value ===))"
|
|
if ((length of "\%stop_labels") > 0):
|
|
%lua = (..)
|
|
Lua ".."
|
|
do -- scope for stopping for % = % loop
|
|
\%lua\%stop_labels
|
|
end
|
|
|
|
return %lua
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
test:
|
|
if:
|
|
(1 == 2) (100 < 0):
|
|
barf "bad conditional"
|
|
(1 == 0) (1 == 1) %not_a_variable.x: do nothing
|
|
(1 == 1):
|
|
barf "bad conditional"
|
|
(1 == 2):
|
|
barf "bad conditional"
|
|
else:
|
|
barf "bad conditional"
|
|
|
|
# Multi-branch conditional (if..elseif..else)
|
|
compile [if %body, when %body] to:
|
|
%code = (Lua "")
|
|
%clause = "if"
|
|
%else_allowed = (yes)
|
|
unless (%body.type is "Block"):
|
|
compile error at %body.source "'if' expected a Block, but got: %s"
|
|
for %line in %body:
|
|
unless (..)
|
|
((%line.type is "Action") and ((length of %line) >= 2)) and (..)
|
|
%line.(length of %line) is "Block" syntax tree
|
|
..:
|
|
compile error at %line.source ".."
|
|
Invalid line for 'if', each line should contain conditional expressions followed by a block, or "else" followed by a block:
|
|
%s
|
|
|
|
%action = %line.(length of %line)
|
|
if ((%line.1 is "else") and ((length of %line) == 2)):
|
|
unless %else_allowed:
|
|
compile error at %line.source "Can't have two 'else' blocks"
|
|
unless ((length of "\%code") > 0):
|
|
compile error at %line.source ".."
|
|
Can't have an 'else' block without a preceeding condition
|
|
|
|
to %code write ".."
|
|
|
|
else
|
|
\(%action as lua statements)
|
|
|
|
%else_allowed = (no)
|
|
..else:
|
|
to %code write "\%clause "
|
|
for %i in 1 to ((length of %line) - 1):
|
|
unless (%line.%i is syntax tree):
|
|
compile error at %line.source ".."
|
|
Invalid condition for 'if' statement:
|
|
%s
|
|
|
|
if (%i > 1):
|
|
to %code write " or "
|
|
to %code write (%line.%i as lua expr)
|
|
|
|
to %code write ".."
|
|
then
|
|
\(%action as lua statements)
|
|
|
|
%clause = "\nelseif"
|
|
|
|
if ((length of "\%code") == 0):
|
|
compile error at %body.source "'if' block has an empty body"
|
|
to %code write "\nend --when"
|
|
return %code
|
|
|
|
test:
|
|
if 5 is:
|
|
1 2 3:
|
|
barf "bad switch statement"
|
|
4 5: do nothing
|
|
5 6:
|
|
barf "bad switch statement"
|
|
else:
|
|
barf "bad switch statement"
|
|
|
|
# Switch statement
|
|
compile [if %branch_value is %body, when %branch_value is %body] to:
|
|
%code = (Lua "")
|
|
%clause = "if"
|
|
%else_allowed = (yes)
|
|
unless (%body.type is "Block"):
|
|
compile error at %body.source "'if' expected a Block, but got: %s"
|
|
for %line in %body:
|
|
unless (..)
|
|
((%line.type is "Action") and ((length of %line) >= 2)) and (..)
|
|
%line.(length of %line) is "Block" syntax tree
|
|
..:
|
|
compile error at %line.source ".."
|
|
Invalid line for 'if % is % %', each line should contain expressions followed by a block, or "else" followed by a block:
|
|
%s
|
|
|
|
%action = %line.(length of %line)
|
|
if ((%line.1 is "else") and ((length of %line) == 2)):
|
|
unless %else_allowed:
|
|
compile error at %line.source "Can't have two 'else' blocks"
|
|
unless ((length of "\%code") > 0):
|
|
compile error at %line.source ".."
|
|
Can't have an 'else' block without a preceeding condition
|
|
|
|
to %code write ".."
|
|
|
|
else
|
|
\(%action as lua statements)
|
|
|
|
%else_allowed = (no)
|
|
..else:
|
|
to %code write "\%clause "
|
|
for %i in 1 to ((length of %line) - 1):
|
|
unless (%line.%i is syntax tree):
|
|
compile error at %line.source ".."
|
|
Invalid condition for 'if' statement:
|
|
%s
|
|
|
|
if (%i > 1):
|
|
to %code write " or "
|
|
to %code write "branch_value == \(%line.%i as lua expr)"
|
|
|
|
to %code write ".."
|
|
then
|
|
\(%action as lua statements)
|
|
|
|
%clause = "\nelseif"
|
|
|
|
if ((length of "\%code") == 0):
|
|
compile error at %body.source "'if % is % %' block has an empty body"
|
|
to %code write "\nend --when"
|
|
return (..)
|
|
Lua ".."
|
|
do --if % is
|
|
local branch_value = \(%branch_value as lua expr)
|
|
\%code
|
|
end --if % is
|
|
|
|
# Do/finally
|
|
compile [do %action] to (..)
|
|
Lua ".."
|
|
do
|
|
\(%action as lua statements)
|
|
end --do
|
|
|
|
test:
|
|
%d = {}
|
|
try:
|
|
do:
|
|
%d.x = "bad"
|
|
barf
|
|
..then always: %d.x = "good"
|
|
..and if it barfs: do nothing
|
|
|
|
assume (%d.x == "good")
|
|
|
|
compile [do %action then always %final_action] to (..)
|
|
Lua ".."
|
|
do
|
|
local fell_through = false
|
|
local ok, ret = pcall(function()
|
|
\(%action as lua statements)
|
|
fell_through = true
|
|
end)
|
|
\(%final_action as lua statements)
|
|
if not ok then error(ret, 0) end
|
|
if not fell_through then return ret end
|
|
end
|
|
|
|
test:
|
|
assume ((result of (: return 99)) == 99)
|
|
|
|
# Inline thunk:
|
|
compile [result of %body] to (Lua value "(\(compile as ([] -> %body)))()")
|
|
test:
|
|
%t = [1, [2, [[3], 4], 5, [[[6]]]]]
|
|
%flat = []
|
|
for % in recursive %t:
|
|
if ((type of %) is "table"):
|
|
for %2 in %: recurse % on %2
|
|
..else: add % to %flat
|
|
|
|
assume ((sorted %flat) == [1, 2, 3, 4, 5, 6])
|
|
|
|
# Recurion control flow
|
|
compile [for %var in recursive %structure %body] to (..)
|
|
with local compile actions:
|
|
compile [recurse %v on %x] to (..)
|
|
Lua "table.insert(stack\(%v as lua id), \(%x as lua expr))"
|
|
%lua = (..)
|
|
Lua ".."
|
|
do
|
|
local stack\(%var as lua id) = list{\(%structure as lua expr)}
|
|
while #stack\(%var as lua id) > 0 do
|
|
\(%var as lua expr) = table.remove(stack\(%var as lua id), 1)
|
|
\(%body as lua statements)
|
|
|
|
if (%body has subtree \(do next)):
|
|
to %lua write "\n ::continue::"
|
|
if (%body has subtree (\(do next %v) with vars {v:%var})):
|
|
to %lua write "\n \(compile as (===next %var ===))"
|
|
to %lua write "\n end -- Recursive loop"
|
|
if (%body has subtree (\(stop %v) with vars {v:%var})):
|
|
to %lua write "\n \(compile as (===stop %var ===))"
|
|
to %lua write "\nend -- Recursive scope"
|
|
return %lua
|