Better error messaging (using pretty_error in more places)

8 files changed, 101 insertions, 200 deletions

diff --git a/lib/compatibility/3.5.5.6.nom b/lib/compatibility/3.5.5.6.nom
index d9bba4f..9887498 100644
--- a/lib/compatibility/3.5.5.6.nom
+++ b/lib/compatibility/3.5.5.6.nom
@@ -8,4 +8,4 @@ use "compatibility/compatibility"
 
 upgrade action "traceback" to "3.5.5.6" via
     for $tree:
-        compile error at $tree "'traceback' has been deprecated."
+        at $tree fail "Upgrade error: 'traceback' has been deprecated."
diff --git a/lib/compatibility/3.nom b/lib/compatibility/3.nom
index 966dbf9..6ce3fdc 100644
--- a/lib/compatibility/3.nom
+++ b/lib/compatibility/3.nom
@@ -11,5 +11,7 @@ upgrade action (me) to "3" as $me
 upgrade action (@) to "3" as $me
 upgrade action "as" to "3" via
     for $tree:
-        compile error at $tree "Object API has changed and 'as' is no longer supported."
-            "Use ($obj, action ...) instead of (as $obj: action ...)"
+        at $tree fail ("
+            Upgrade error: Object API has changed and 'as' is no longer supported.
+            Hint: Use ($obj, action ...) instead of (as $obj: action ...)
+        ")
diff --git a/lib/compatibility/4.11.nom b/lib/compatibility/4.11.nom
index 88ea7b3..053e1c8 100644
--- a/lib/compatibility/4.11.nom
+++ b/lib/compatibility/4.11.nom
@@ -29,8 +29,10 @@ upgrade action "set" to "4.11" via
 
 upgrade action "1 with 2 ~>" to "4.11" via
     for $tree:
-        compile error at $tree "This method has been deprecated."
-            "Perhaps this could be use ($tree, map ...) instead."
+        at $tree fail ("
+            Upgrade error: This method has been deprecated.
+            Hint: Perhaps this could be use ($tree, map ...) instead.
+        ")
 
 # Changing filesystem API:
 upgrade action (for file $f in $path $body) to "4.11" as
diff --git a/lib/compatibility/4.12.nom b/lib/compatibility/4.12.nom
index bb1af0b..033f6ed 100644
--- a/lib/compatibility/4.12.nom
+++ b/lib/compatibility/4.12.nom
@@ -9,10 +9,14 @@ use "compatibility/compatibility"
 
 upgrade action "do next repeat" to "4.12" via
     for $tree:
-        compile error at $tree "This method has been deprecated."
-            "Use either (do next) or (go to (label)) instead."
+        at $tree fail ("
+            Upgrade error: This method has been deprecated.
+            Hint: Use either (do next) or (go to (label)) instead.
+        ")
 
 upgrade action "stop repeating" to "4.12" via
     for $tree:
-        compile error at $tree "This method has been deprecated."
-            "Use either (stop) or (go to (label)) instead."
+        at $tree fail ("
+            Upgrade error: This method has been deprecated.
+            Hint: Use either (stop) or (go to (label)) instead.
+        ")
diff --git a/lib/core/control_flow.nom b/lib/core/control_flow.nom
index 715630b..c4c1770 100644
--- a/lib/core/control_flow.nom
+++ b/lib/core/control_flow.nom
@@ -328,29 +328,34 @@ test:
     $clause = "if"
     $else_allowed = (yes)
     unless ($body.type is "Block"):
-        compile error at $body "'if' expected a Block, but got a \($body.type)."
-            "Perhaps you forgot to put a ':' after 'if'?"
+        at $body fail ("
+            Compile error: 'if' expected a Block, but got a \($body.type).
+            Hint: Perhaps you forgot to put a ':' after 'if'?
+        ")
     
     for $line in $body:
         unless
             (($line.type is "Action") and ((size of $line) >= 2)) and
                 $line.(size of $line) is "Block" syntax tree
         ..:
-            compile error at $line "Invalid line for the body of an 'if' block." ("
-                Each line should contain one or more conditional expressions followed by a block, or "else"\
-                .. followed by a block.
+            at $line fail ("
+                Compile error: Invalid line for the body of an 'if' block.
+                Hint: Each line should contain one or more conditional expressions followed \
+                ..by a block, or "else" followed by a block.
             ")
         $action = $line.(size of $line)
         if (($line.1 is "else") and ((size of $line) == 2)):
             unless $else_allowed:
-                compile error at $line "You can't have two 'else' blocks."
-                    "Merge all of the 'else' blocks together."
+                at $line fail ("
+                    Compile error: You can't have two 'else' blocks.
+                    Hint: Merge all of the 'else' blocks together.
+                ")
             
             unless ((size of "\$code") > 0):
-                compile error at $line
-                .."You can't have an 'else' block without a preceding condition" ("
-                    If you want the code in this block to always execute, you don't need a conditional block \
-                    ..around it. Otherwise, make sure the 'else' block comes last.
+                at $line fail ("
+                    Compile error: You can't have an 'else' block without a preceding condition.
+                    Hint: If you want the code in this block to always execute, you don't need a \
+                    ..conditional block around it. Otherwise, make sure the 'else' block comes last.
                 ")
             
             $code, add "\nelse\n    " ($action as lua)
@@ -365,8 +370,10 @@ test:
             $clause = "\nelseif"
     
     if ((size of "\$code") == 0):
-        compile error at $body "'if' block has an empty body."
-            "This means nothing would happen, so the 'if' block should be deleted."
+        at $body fail ("
+            Compile error: 'if' block has an empty body.
+            Hint: This means nothing would happen, so the 'if' block should be deleted.
+        ")
     
     $code, add "\nend --when"
     return $code
@@ -392,28 +399,33 @@ test:
     $else_allowed = (yes)
     define mangler
     unless ($body.type is "Block"):
-        compile error at $body "'if' expected a Block, but got a \($body.type)"
-            "Perhaps you forgot to put a ':' after the 'is'?"
+        at $body fail ("
+            Compile error: 'if' expected a Block, but got a \($body.type).
+            Hint: Perhaps you forgot to put a ':' after the 'is'?
+        ")
     
     for $line in $body:
         unless
             (($line.type is "Action") and ((size of $line) >= 2)) and
                 $line.(size of $line) is "Block" syntax tree
         ..:
-            compile error at $line "Invalid line for 'if' block." ("
-                Each line should contain expressions followed by a block, or "else" followed by a block
+            at $line fail ("
+                Compile error: Invalid line for 'if' block.
+                Hint: Each line should contain expressions followed by a block, or "else" followed by a block.
             ")
         $action = $line.(size of $line)
         if (($line.1 is "else") and ((size of $line) == 2)):
             unless $else_allowed:
-                compile error at $line "You can't have two 'else' blocks."
-                    "Merge all of the 'else' blocks together."
+                at $line fail ("
+                    Compile error: You can't have two 'else' blocks.
+                    Hint: Merge all of the 'else' blocks together.
+                ")
             
             unless ((size of "\$code") > 0):
-                compile error at $line
-                .."You can't have an 'else' block without a preceding condition" ("
-                    If you want the code in this block to always execute, you don't need a conditional block \
-                    ..around it. Otherwise, make sure the 'else' block comes last.
+                at $line fail ("
+                    Compile error: You can't have an 'else' block without a preceding condition.
+                    Hint: If you want the code in this block to always execute, you don't need \
+                    ..a conditional block around it. Otherwise, make sure the 'else' block comes last.
                 ")
             
             $code, add "\nelse\n    " ($action as lua)
@@ -428,8 +440,10 @@ test:
             $clause = "\nelseif"
     
     if ((size of "\$code") == 0):
-        compile error at $body "'if' block has an empty body."
-            "This means nothing would happen, so the 'if' block should be deleted."
+        at $body fail ("
+            Compile error: 'if' block has an empty body.
+            Hint: This means nothing would happen, so the 'if' block should be deleted.
+        ")
     
     $code, add "\nend --when"
     return
diff --git a/lib/core/errors.nom b/lib/core/errors.nom
index 9a2cc9b..0b67400 100644
--- a/lib/core/errors.nom
+++ b/lib/core/errors.nom
@@ -8,32 +8,36 @@ use "core/control_flow"
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-(fail $msg) compiles to "error(\(($msg as lua expr) if $msg else "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
-        ")
+(fail $msg) compiles to
+    LuaCode
+        "at_1_fail(\(quote $msg.source), 'Failure: '..\($msg as lua expr))"
+        ..if $msg else "error('Failure', 0)"
 
-(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) compiles to ("
+    if not \($condition as lua expr) then
+        at_1_fail(\(quote "\($condition.source)"), "Assumption failed: This is not true.")
+    end
+")
+
+(assume $a == $b) compiles to ("
+    do
+        local _a, _b = \($a as lua expr), \($b as lua expr)
+        if _a ~= _b then
+            at_1_fail(\(quote "\($a.source)"),
+                "Assumption failed: This value is "..tostring(_a)..", but it was supposed to be "..tostring(_b)..".")
+        end
+    end
+")
+
+(assume $a != $b) compiles to ("
+    do
+        local _a, _b = \($a as lua expr), \($b as lua expr)
+        if _a == _b then
+            at_1_fail(\(quote "\($a.source)"),
+                "Assumption failed: This value is "..tostring(_a)..", but it wasn't supposed to be.")
+        end
+    end
+")
 
 test:
     try: fail
@@ -44,7 +48,7 @@ test:
         $worked = (yes)
     ..if it succeeds:
         fail "'try' incorrectly ran success case."
-    assume $failure == "xx"
+    assume ($failure, matches "xx")
     unless $worked:
         fail "'try' failed to recover from failure"
 
diff --git a/lib/core/metaprogramming.nom b/lib/core/metaprogramming.nom
index 9b3d5c4..a17a33c 100644
--- a/lib/core/metaprogramming.nom
+++ b/lib/core/metaprogramming.nom
@@ -34,14 +34,15 @@ lua> ("
             local arg_lua = SyntaxTree:is_instance(arg) and \(nomsu environment):compile(arg):text() or arg
             if arg_lua == "..." then
                 if i < #\$args then
-                    compile_error_at(SyntaxTree:is_instance(arg) and arg or nil,
-                        "Extra arguments must come last.", "Try removing any arguments after \
-    ..(*extra arguments*)")
+                    at_1_fail(SyntaxTree:is_instance(arg) and arg or nil,
+                        "Compile error: Extra arguments must come last. "..
+                        "Hint: Try removing any arguments after (*extra arguments*)")
                 end
             elseif not arg_lua:is_lua_id() then
-                compile_error_at(SyntaxTree:is_instance(arg) and arg or nil,
-                    "This does not compile to a Lua identifier, so it can't be used as a function argument.",
-                    "This should probably be a Nomsu variable instead (like $x).")
+                at_1_fail(SyntaxTree:is_instance(arg) and arg or nil,
+                    "Compile error: This does not compile to a Lua identifier, so it "..
+                    "can't be used as a function argument."..
+                    "Hint: This should probably be a Nomsu variable instead (like $x).")
             end
             lua:add(i > 1 and ", " or "", arg_lua)
             body_lua:remove_free_vars({arg_lua})
@@ -98,7 +99,7 @@ lua> ("
 ($actions all compile to $body) compiles to:
     lua> ("
         if \$actions.type ~= "List" then
-            compile_error(\$actions, "This should be a list of actions.")
+            at_1_fail(\$actions, "Compile error: This should be a list of actions.")
         end
         local lua = \(\($actions.1 compiles to $body) as lua)
         local \$args = List{"\(nomsu environment)", unpack(\$actions[1]:get_args())}
@@ -151,7 +152,7 @@ test:
             lua:add(\$action:get_stub():as_lua_id())
             lua:add_free_vars({\$action:get_stub():as_lua_id()})
         else
-            compile_error_at(\$action, "Expected an action or method call here")
+            at_1_fail(\$action, "Compile error: Expected an action or method call here")
         end
         lua:add(" = ", \(\($action -> $body) as lua), ";")
         return lua
@@ -241,7 +242,7 @@ test:
     lua> ("
         local replacements = {}
         if \$actions.type ~= "List" then
-            compile_error(\$actions, "This should be a list.")
+            at_1_fail(\$actions, "Compile error: This should be a list.")
         end
         for i,arg in ipairs(\$actions[1]:get_args()) do
             replacements[arg[1]] = \(nomsu environment):compile(arg):text()
@@ -293,9 +294,8 @@ external:
             if \$tree.type == 'Block' then
                 tree_lua = LuaCode:from(\$tree.source, '(function()\\n    ', tree_lua, '\\nend)()')
             elseif \$tree.type == 'MethodCall' and #\$tree > 2 then
-                compile_error_at(\$tree, "This must be a single value instead of "..(#\$tree - 1).."\
-            .. method calls.",
-                    "Replace this with a single method call.")
+                at_1_fail(\$tree, "Compile error: This must be a single value instead of "..
+                (#\$tree - 1).." method calls. Hint: Replace this with a single method call.")
             end
             return tree_lua
         ")
@@ -311,9 +311,9 @@ external:
         lua> ("
             local lua = \($var as lua)
             if not lua:text():is_a_lua_id() then
-                compile_error(\$var,
-                    "This is supposed to be something that compiles to a valid Lua identifier.",
-                    "This should probably be a variable.")
+                at_1_fail(\$var, "Compile error: "..
+                    "This is supposed to be something that compiles to a valid Lua identifier. "..
+                    "Hint: This should probably be a variable.")
             end
             return lua
         ")
diff --git a/lib/object.nom b/lib/object.nom
deleted file mode 100644
index 99981a0..0000000
--- a/lib/object.nom
+++ /dev/null
@@ -1,125 +0,0 @@
-#!/usr/bin/env nomsu -V6.15.13.8
-#
-    This file contains the implementation of an Object-Oriented programming system.
-    
-$globals.METAMETHOD_MAP = {
-    ."as text" = "__tostring", ."clean up" = "__gc", ."+ 1" = "__add"
-    ."- 1" = "__sub", ."* 1" = "__mul", ."/ 1" = "__div", ."-" = "__unm"
-    ."// 1" = "__idiv", ."mod 1" = "__mod", ."^ 1" = "__pow", ."& 1" = "__band"
-    ."| 1" = "__bor", ."~ 1" = "__bxor", ."~" = "__bnot", ."<< 1" = "__bshl"
-    .">> 1" = "__bshr", ."== 1" = "__eq", ."< 1" = "__lt", ."<= 1" = "__le"
-    ."set 1 = 2" = "__newindex", .size = "__len", .iterate = "__ipairs"
-    ."iterate all" = "__pairs"
-}
-
-test:
-    object (Dog):
-        (Dog).genus = "Canus"
-        my action [set up]:
-            $me.barks or= 0
-        
-        my action [bark, woof]:
-            $barks = [: for $ in 1 to $me.barks: add "Bark!"]
-            return ($barks, joined with " ")
-        
-        my action [get pissed off]: $me.barks += 1
-    $d = (Dog {.barks = 2})
-    assume (type of $d) == "Dog"
-    assume ($d is a "Dog")
-    assume $d.barks == 2
-    assume (($d, bark) == "Bark! Bark!")
-    assume (($d, woof) == "Bark! Bark!")
-    $d, get pissed off
-    assume ($d.barks == 3)
-    assume (($d, bark) == "Bark! Bark! Bark!")
-    assume ($d.genus == "Canus")
-    assume ("\($d.class)" == "Dog")
-    assume ($d.genus == "Canus")
-    assume ($d.barks == 3)
-    $d2 = (Dog {})
-    unless ($d2.barks == 0):
-        fail "Default initializer failed"
-    
-    with [$d = (Dog {.barks = 1})]:
-        assume (($d, bark) == "Bark!")
-    
-    object (Corgi) extends (Dog):
-        my action [sploot] "splooted"
-        my action [bark, woof]:
-            $barks = [: for $ in 1 to $me.barks: add "Yip!"]
-            return ($barks, joined with " ")
-    
-    $corg = (Corgi {})
-    assume ($corg.barks == 0)
-    with [$d = (Corgi {.barks = 1})]:
-        unless (($d, sploot) == "splooted"):
-            fail "subclass method failed"
-        
-        unless (($d, bark) == "Yip!"):
-            fail "inheritance failed"
-        
-        assume (($d, woof) == "Yip!")
-    
-    with [$d = (Dog {.barks = 2})]:
-        assume (($d, bark) == "Bark! Bark!")
-
-(my action $actions $body) compiles to:
-    lua> ("
-        local fn_name = \$actions[1].stub:as_lua_id()
-        local \$args = List(\$actions[1]:get_args())
-        table.insert(\$args, 1, \(\$me))
-        local lua = LuaCode("class.", fn_name, " = ", \(\($args -> $body) as lua))
-        for i=2,#\$actions do
-            local alias = \$actions[i]
-            local alias_name = alias.stub:as_lua_id()
-            local \$alias_args = List(alias:get_args())
-            table.insert(\$alias_args, 1, \(\$me))
-            lua:add("\\nclass.", alias_name, " = ")
-            if \$args == \$alias_args then
-                lua:add("class.", fn_name)
-            else
-                lua:add(\(\($alias_args -> $actions.1) as lua))
-            end
-        end
-        return lua
-    ")
-
-(object $classname extends $parent $class_body) compiles to:
-    unless ($classname.type == "Action"):
-        compile error at $classname
-            "Expected this to be an action, not a \$classname.type"
-    
-    for $ in $classname:
-        unless ($ is text):
-            compile error at $ "Class names should not have arguments."
-    
-    return
-        Lua ("
-            do
-                local class = {name=\(quote $classname.stub)}
-                class.__type = class.name
-                setmetatable(class, {
-                    __index=\($parent as lua expr),
-                    __tostring=function(cls) return cls.name end,
-                    __call=function(cls, inst)
-                        if inst == nil then return cls end
-                        inst = setmetatable(inst, cls)
-                        if inst.set_up then inst:set_up() end
-                        return inst
-                    end,
-                })
-                \(nomsu environment name)[class.name:as_lua_id()] = class
-                class.__index = class
-                class.class = class
-                class.__tostring = function(inst)
-                    return inst.name..getmetatable(Dict{}).__tostring(inst)
-                end
-                \($class_body as lua)
-                for stub,metamethod in pairs(globals.METAMETHOD_MAP) do
-                    class[metamethod] = class[stub:as_lua_id()]
-                end
-            end
-        ")
-
-(object $classname $class_body) parses as
-    object $classname extends (nil) $class_body