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#!/usr/bin/env nomsu -V6.13.12.8
#
This file contains basic error reporting code
use "core/metaprogramming.nom"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(barf $msg) compiles to
"error(\(=lua "\$msg and \($msg as lua expr) or 'nil'"), 0);"
(assume $condition) compiles to:
lua> ("
local \$assumption = 'Assumption failed: '..tostring((\$condition):get_source_code())
")
return
Lua ("
if not \($condition as lua expr) then
error(\(quote "\$assumption"), 0)
end
")
(assume $a == $b) compiles to:
lua> "local \$assumption = 'Assumption failed: '..tostring(\(\($a == $b) as nomsu))"
define mangler
return
Lua ("
do
local \(mangle "a"), \(mangle "b") = \($a as lua expr), \($b as lua expr)
if \(mangle "a") ~= \(mangle "b") then
error(\(quote "\$assumption").."\\n"..tostring(\(mangle "a")).." != "..tostring(\
..\(mangle "b")), 0)
end
end
")
(assume $condition or barf $message) compiles to ("
if not \($condition as lua expr) then
error(\($message as lua expr), 0)
end
")
test:
try (barf) and if it succeeds:
barf "try failed."
$worked = (no)
try (barf) and if it barfs:
$worked = (yes)
assume $worked or barf "try/catch failed"
$x = 1
try:
$x = 2
do (barf) then always: $x = 3
..and if it barfs:
do nothing
assume ($x == 3) or barf "do/then always failed"
# Try/except
[
try $action and if it succeeds $success or if it barfs $msg $fallback
try $action and if it barfs $msg $fallback or if it succeeds $success
] all compile to ("
do
local fell_through = false
local err, erred = nil, false
local ok, ret = xpcall(function()
\($action as lua)
fell_through = true
end, function(\(=lua "\$fallback and \($msg as lua expr) or ''"))
local ok, ret = pcall(function()
\((=lua "\$fallback or \$msg") as lua)
end)
if not ok then err, erred = ret, true end
end)
if ok then
\($success as lua)
if not fell_through then
return ret
end
elseif erred then
error(err, 0)
end
end
")
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(try $action) parses as
try $action and if it succeeds (do nothing) or if it barfs (do nothing)
(try $action and if it barfs $msg $fallback) parses as
try $action and if it succeeds (do nothing) or if it barfs $msg $fallback
(try $action and if it succeeds $success) parses as
try $action and if it succeeds $success or if it barfs (do nothing)
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