nomsu/core/operators.nom
Bruce Hill b6d3cbd61c Misc changes, including text indented interpolations are now indented
relative to the text, not the opening '("', code objects can now remove
all free vars, the REPL uses global vars. Error API is changing a bit.
2019-01-01 15:07:10 -08:00

244 lines
8.6 KiB
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#!/usr/bin/env nomsu -V6.13.12.8
#
This file contains definitions of operators like "+" and "and".
use "core/metaprogramming.nom"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test:
assume (all [1 < 2, 2 > 1, 1 <= 2, 2 >= 1, 1 == 1, 1 != 2])
# Comparison Operators
($x < $y) compiles to "(\($x as lua expr) < \($y as lua expr))"
($x > $y) compiles to "(\($x as lua expr) > \($y as lua expr))"
($x <= $y) compiles to "(\($x as lua expr) <= \($y as lua expr))"
($x >= $y) compiles to "(\($x as lua expr) >= \($y as lua expr))"
[$a is $b, $a == $b] all compile to "(\($a as lua expr) == \($b as lua expr))"
[$a isn't $b, $a is not $b, $a not= $b, $a != $b] all compile to
"(\($a as lua expr) ~= \($b as lua expr))"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test:
$x = 10
assume ($x == 10)
[$x, $y] = [10, 20]
assume (($x == 10) and ($y == 20)) or barf "mutli-assignment failed."
[$x, $y] = [$y, $x]
assume (($y == 10) and ($x == 20)) or barf "swapping vars failed."
$vals = [4, 5]
[$x, $y] = (unpack $vals)
assume (($x == 4) and ($y == 5)) or barf "unpacking failed"
# Variable assignment operator
($var = $value) compiles to:
lua> ("
local lua = LuaCode()
if \$var.type == "List" then
for i, \$assignment in ipairs(\$var) do
if i > 1 then lua:add(", ") end
local assignment_lua = \($assignment as lua expr)
lua:add(assignment_lua)
if \$assignment.type == 'Var' then
lua:add_free_vars({assignment_lua:text()})
end
end
lua:add(' = ')
if \$value.type == "List" then
if #\$value ~= #\$var then
compile_error_at(\$value,
"This assignment has too "..(#\$value > #\$var and "many" or "few").." values.",
"Make sure it has the same number of values on the left and right hand side \
..of the '=' operator.")
end
for i, \$val in ipairs(\$value) do
if i > 1 then lua:add(", ") end
local val_lua = \($val as lua expr)
lua:add(val_lua)
end
lua:add(";")
else
lua:add(\($value as lua expr), ';')
end
else
local var_lua = \($var as lua expr)
lua:add(var_lua)
if \$var.type == 'Var' then
lua:add_free_vars({var_lua:text()})
end
lua:add(' = ', \($value as lua expr))
end
return lua
")
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test:
[$foozle, $y] = ["outer", "outer"]
externally (set global x local y) means:
external $foozle = "inner"
$y = "inner"
set global x local y
assume (($foozle == "inner") and ($y == "outer")) or barf "external failed."
(external $var = $value) compiles to "\($var as lua) = \($value as lua)"
test:
[$foozle, $y] = ["outer", "outer"]
externally (set global x local y) means:
with external [$foozle]:
$foozle = "inner"
$y = "inner"
set global x local y
assume (($foozle == "inner") and ($y == "outer")) or barf
"'with external' failed."
(with external $externs $body) compiles to:
$body_lua = ($body as lua)
lua> ("
\$body_lua:remove_free_vars(table.map(\$externs, function(v) return compile(v):text() end))
")
return $body_lua
test:
[$x, $y] = [1, 2]
with [$z, $x = 999]:
assume $z == (nil)
$z = 999
assume ($z == 999) or barf "'with' failed."
assume ($x == 999) or barf "'with' assignment failed."
assume ($x == 1) or barf "'with' scoping failed"
assume ($z == (nil)) or barf "'with' scoping failed"
(with $assignments $body) compiles to:
lua> ("
local \$defs = LuaCode()
for i, \$item in ipairs(\$assignments) do
if i > 1 then \$defs:add("\\n") end
local item_lua = \($item as lua)
if \$item.type == 'Action' and \$item.stub == '1 =' then
item_lua:remove_free_vars(item_lua.free_vars)
end
\$defs:add("local ", item_lua, ";")
end
")
return
Lua ("
do
\$defs
\($body as lua)
end -- 'with' block
")
# Math Operators
test:
assume ((5 wrapped around 2) == 1) or barf "mod not working"
[$x wrapped around $y, $x mod $y] all compile to
"((\($x as lua expr)) % (\($y as lua expr)))"
# 3-part chained comparisons
# (uses a lambda to avoid re-evaluating middle value, while still being an expression)
test:
$calls = 0
(one) means:
external $calls = ($calls + 1)
return 1
assume (0 <= (one) <= 2) or barf "Three-way chained comparison failed."
assume ($calls == 1) or barf
"Three-way comparison evaluated middle value multiple times"
($x < $y < $z) parses as ((($a $b $c) -> (($a < $b) and ($b < $c))) $x $y $z)
($x <= $y < $z) parses as ((($a $b $c) -> (($a <= $b) and ($b < $c))) $x $y $z)
($x < $y <= $z) parses as ((($a $b $c) -> (($a < $b) and ($b <= $c))) $x $y $z)
($x <= $y <= $z) parses as ((($a $b $c) -> (($a <= $b) and ($b <= $c))) $x $y $z)
($x > $y > $z) parses as ((($a $b $c) -> (($a > $b) and ($b > $c))) $x $y $z)
($x >= $y > $z) parses as ((($a $b $c) -> (($a >= $b) and ($b > $c))) $x $y $z)
($x > $y >= $z) parses as ((($a $b $c) -> (($a > $b) and ($b >= $c))) $x $y $z)
($x >= $y >= $z) parses as ((($a $b $c) -> (($a >= $b) and ($b >= $c))) $x $y $z)
# TODO: optimize for common case where x,y,z are all either variables or number literals
# Boolean Operators
test:
(barfer) means (barf "short circuiting failed")
assume (((no) and (barfer)) == (no))
assume ((no) or (yes))
assume ((yes) or (barfer))
($x and $y) compiles to "(\($x as lua expr) and \($y as lua expr))"
($x or $y) compiles to "(\($x as lua expr) or \($y as lua expr))"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Bitwise Operators
# TODO: implement OR, XOR, AND for multiple operands?
test:
assume ((~ (~ 5)) == 5)
assume ((1 | 4) == 5)
assume ((1 ~ 3) == 2)
assume ((1 & 3) == 1)
assume ((1 << 2) == 4)
assume ((4 >> 2) == 1)
# Lua 5.3 introduced bit operators like | and &. Use them when possible, otherwise
fall back to bit.bor(), bit.band(), etc.
lua> "if \((is jit) or ((Lua version) == "Lua 5.2")) then"
[NOT $, ~ $] all compile to "bit.bnot(\($ as lua expr))"
[$x OR $y, $x | $y] all compile to
"bit.bor(\($x as lua expr), \($y as lua expr))"
[$x XOR $y, $x ~ $y] all compile to
"bit.bxor(\($x as lua expr), \($y as lua expr))"
[$x AND $y, $x & $y] all compile to
"bit.band(\($x as lua expr), \($y as lua expr))"
[$x LSHIFT $shift, $x << $shift] all compile to
"bit.lshift(\($x as lua expr), \($shift as lua expr))"
[$x RSHIFT $shift, $x >> $shift] all compile to
"bit.rshift(\($x as lua expr), \($shift as lua expr))"
lua> "else"
[NOT $, ~ $] all compile to "~(\($ as lua expr))"
[$x OR $y, $x | $y] all compile to "(\($x as lua expr) | \($y as lua expr))"
[$x XOR $y, $x ~ $y] all compile to "(\($x as lua expr) ~ \($y as lua expr))"
[$x AND $y, $x & $y] all compile to "(\($x as lua expr) & \($y as lua expr))"
[$x LSHIFT $shift, $x << $shift] all compile to
"(\($x as lua expr) << \($shift as lua expr))"
[$x RSHIFT $shift, $x >> $shift] all compile to
"(\($x as lua expr) >> \($shift as lua expr))"
lua> "end"
# Unary operators
test:
assume ((- 5) == -5)
assume ((not (yes)) == (no))
(- $) compiles to "(- \($ as lua expr))"
(not $) compiles to "(not \($ as lua expr))"
test:
assume ((size of [1, 2, 3]) == 3)
assume ((#[1, 2, 3]) == 3)
[#$list, size of $list] all compile to "(#\($list as lua expr))"
($list is empty) compiles to "(#\($list as lua expr) == 0)"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Update operators
test:
$x = 1
$x += 1
assume ($x == 2) or barf "+= failed"
$x *= 2
assume ($x == 4) or barf "*= failed"
wrap $x around 3
assume ($x == 1) or barf "wrap around failed"
($var += $) parses as ($var = (($var or 0) + $))
($var -= $) parses as ($var = (($var or 0) - $))
($var *= $) parses as ($var = (($var or 1) * $))
($var /= $) parses as ($var = ($var / $))
($var ^= $) parses as ($var = ($var ^ $))
($var and= $) parses as ($var = ($var and $))
($var or= $) parses as ($var = ($var or $))
(wrap $var around $) parses as ($var = ($var wrapped around $))