Merge branch 'master' of ssh://git.eclipse.org/gitroot/koneki/org.eclipse.koneki...

[metalua.git] / checks.lua

diff --git a/checks.lua b/checks.lua
new file mode 100644 (file)
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--- /dev/null
+++ b/checks.lua
@@ -0,0 +1,59 @@
+--------------------------------------------------------------------------------
+-- Copyright (c) 2006-2013 Fabien Fleutot and others.
+--
+-- All rights reserved.
+--
+-- This program and the accompanying materials are made available
+-- under the terms of the Eclipse Public License v1.0 which
+-- accompanies this distribution, and is available at
+-- http://www.eclipse.org/legal/epl-v10.html
+--
+-- This program and the accompanying materials are also made available
+-- under the terms of the MIT public license which accompanies this
+-- distribution, and is available at http://www.lua.org/license.html
+--
+-- Contributors:
+--     Fabien Fleutot - API and implementation
+--
+--------------------------------------------------------------------------------
+
+-- Alternative implementation of checks() in Lua. Slower than
+-- the C counterpart, but no compilation/porting concerns.
+
+checkers = { }
+
+local function check_one(expected, val)
+    if type(val)==expected then return true end
+    local mt = getmetatable(val)
+    if mt and mt.__type==expected then return true end
+    local f = checkers[expected]
+    if f and f(val) then return true end
+    return false
+end
+
+local function check_many(name, expected, val)
+    if expected=='?' then return true
+    elseif expected=='!' then return (val~=nil)
+    elseif type(expected) ~= 'string' then
+        error 'strings expected by checks()'
+    elseif val==nil and expected :sub(1,1) == '?' then return true end
+    for one in expected :gmatch "[^|?]+" do
+        if check_one(one, val) then return true end
+    end
+    return false
+end
+
+function checks(...)
+    for i, arg in ipairs{...} do
+        local name, val = debug.getlocal(2, i)
+        local success = check_many(name, arg, val)
+        if not success then
+            local fname = debug.getinfo(2, 'n').name
+            local fmt = "bad argument #%d to '%s' (%s expected, got %s)"
+            local msg = string.format(fmt, i, fname or "?", arg, type(val))
+            error(msg, 3)
+        end
+    end
+end
+
+return checks