proper error handling in ROMBASIC

Former-commit-id: b5bd084e6807c765cdd6d3ffff1b1628321b9c6a
Former-commit-id: 55c3bb3cd56c7867809c0819f178aeebf1e46676

src/net/torvald/terrarum/virtualcomputer/assets/lua/BOOT.lua

@@ -19,8 +19,8 @@ _G.DLE = string.char(16) -- default error colour
 _G.getMem = function() collectgarbage() return collectgarbage("count") * 1024 end
 -- getTotalMem: implemented in Kotlin class
 _G.getFreeMem = function() return getTotalMem() - getMem() end
-_G.runscript = function(s, env)
-    local code, reason = load(s, env)
+_G.runscript = function(s, source, ...)
+    local code, reason = load(s, source)
 
     if _G.getFreeMem() <= 0 then
         print("out of memory")
@@ -29,9 +29,9 @@ _G.runscript = function(s, env)
     end
 
     if code then
-        xpcall(code, eprint)
+        xpcall(code(...), eprint)
     else
-        print(DLE..tostring(reason))
+        print(DLE..tostring(reason)) -- it catches syntax errors
     end
 end
 _G.__scanMode__ = "UNINIT" -- part of inputstream implementation
@@ -59,16 +59,22 @@ if shell.status == shell.halt then
 end
 
 -- load Lua prompt, if bios is not found
-if (#_COMPUTER.OEM > 0) then print(_COMPUTER.OEM) end
 print("Rom basic "..DC2.._VERSION..DC4)
+print("Copyright (C) 1994-2015 Lua.org, PUC-Rio")
 print(DC2..tostring(math.floor(getFreeMem()/1024+0.5))..DC4.." Kbytes free")
+print("To boot your system, run 'boot()'")
 print("Ok")
 
 while not native.isHalted() do
-    io.write(_COMPUTER.prompt)
-    local s = io.read()
-    runscript(s, "=stdin")
+    while not native.isHalted() do
+        io.write(_COMPUTER.prompt)
+        local s = io.read()
+        xpcall(
+            function() _G.runscript(s, "=stdin") end,
+            function(s) print(DLE..s) end -- it catches logical errors
+        )
+    end
 end
-
 native.closeInputString()
+__haltsystemexplicit__()
 return

src/net/torvald/terrarum/virtualcomputer/assets/lua/ROMLIB.lua

@@ -6,10 +6,10 @@
 -- ALIASES --
 -------------
 
-fs.dofile = function(p)
+fs.dofile = function(p, ...)
     local f = fs.open(p, "r")
     local s = f.readAll()
-    _G.runscript(s, "="..p)
+    _G.runscript(s, "="..p, ...)
 end
 
 _G.loadstring = _G.load
@@ -18,6 +18,15 @@ _G.print = term.print
 
 --_G.dofile = function(f) fs.dofile(f) end
 
+_G.boot = function() fs.dofile("/boot/efi") end
+
+
+fs.fetchText = function(p)
+    local file = fs.open(p, "r")
+    local text = file.readAll()
+    file.close()
+    return text
+end
 
 -----------------------------------------
 -- INPUTSTREAM AND SCANNER (java-like) --
@@ -38,9 +47,9 @@ override fun keyPressed(key: Int, c: Char) {
 ...it basically says to close the input if RETURN is hit,
   and THIS exact part will close the input for this function.
 ]]
-_G.__scanForLine__ = function()
+_G.__scanforline__ = function(echo) -- pass '1' to not echo; pass nothing to echo
     native.closeInputString()
-    native.openInput()
+    native.openInput(echo or 0)
     _G.__scanMode__ = "line"
     local s
     repeat -- we can do this ONLY IF lua execution process is SEPARATE THREAD
@@ -51,9 +60,9 @@ _G.__scanForLine__ = function()
 end
 
 -- use Keys API to identify the keycode
-_G.__scanForChar__ = function()
+_G.__scanforchar__ = function(echo) -- pass '1' to not echo; pass nothing to echo
     native.closeInputString()
-    native.openInput()
+    native.openInput(echo or 0)
     _G.__scanMode__ = "a_key"
     local key
     repeat -- we can do this ONLY IF lua execution process is SEPARATE THREAD
@@ -63,7 +72,7 @@ _G.__scanForChar__ = function()
     return key
 end
 
-io.read = _G.__scanForLine__
+io.read = _G.__scanforline__
 
 
 -----------------