diff options
Diffstat (limited to 'core/errors.nom')
| -rw-r--r-- | core/errors.nom | 123 |
1 files changed, 74 insertions, 49 deletions
diff --git a/core/errors.nom b/core/errors.nom index 6779922..0b63b5b 100644 --- a/core/errors.nom +++ b/core/errors.nom @@ -3,11 +3,12 @@ This file contains basic error reporting code use "core/metaprogramming.nom" +use "core/operators.nom" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -(barf $msg) compiles to - "error(\(=lua "\$msg and \($msg as lua expr) or 'nil'"), 0);" +(fail $msg) compiles to + "error(\(($msg as lua expr) if $msg else "nil"), 0);" (assume $condition) compiles to: lua> (" @@ -37,62 +38,86 @@ use "core/metaprogramming.nom" 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." + try: fail $worked = (no) - try (barf) and if it barfs: + try: fail + ..if it fails: $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" - + ..if it succeeds: + fail "'try' incorrectly ran success case." + + unless $worked: + fail "'try' failed to recover from failure" # 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 + try $action if it succeeds $success if it fails $fallback + try $action if it fails $fallback if it succeeds $success +] all compile to: + $success_lua = ($success as lua) + if ((#"\$success_lua") > 0): $success_lua, add "\n" + $success_lua, prepend "-- Success:\n" + $success_lua, add "if not _fell_through then return table.unpack(_result, 2) end" + $fallback_lua = ($fallback as lua) + if ((#"\$fallback_lua") > 0): + $fallback_lua, prepend "\nlocal function failure() return _result[2] end\n" + $fallback_lua, prepend "-- Failure:" + return + Lua (" + do + local _fell_through = false + local _result = {pcall(function() + \($action as lua) + _fell_through = true + end)} + if _result[1] then + \$success_lua + else + \$fallback_lua + end 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 if it succeeds (do nothing) if it fails (do nothing) + +(try $action if it fails $msg $fallback) parses as + try $action if it succeeds (do nothing) if it fails $msg $fallback + +(try $action if it succeeds $success) parses as + try $action if it succeeds $success if it fails (do nothing) + +(try $action if it fails $fallback if it succeeds $success) parses as + try $action if it succeeds $success if it fails $fallback + +test: + $success = (no) + try: + do: fail + ..then always: + $success = (yes) + ..if it succeeds: + fail "'try ... then always ...' didn't propagate failure" + + unless $success: + fail "'try ... then always ...' didn't execute the 'always' code" + +(do $action then always $final_action) compiles to (" + do -- do/then always + local _fell_through = false + local _results = {pcall(function() + \($action as lua) + _fell_through = true + end)} + \($final_action as lua) + if not _results[1] then error(_results[2], 0) end + if not _fell_through then return table.unpack(_results, 2) end + end +") -(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) +(barf $) parses as (fail $) +(assume $1 or barf $2) parses as (unless $1: fail $2) |