error handling: scope + registry

4 files changed, 18 insertions, 10 deletions

diff --git a/core/init.moon b/core/init.moon
index 1aa0d2d..8a0154c 100644
--- a/core/init.moon
+++ b/core/init.moon
@@ -57,7 +57,7 @@ globals = Scope.from_table require 'core.builtin'
       scope = Scope nil, globals
       scope\use inject if inject
 
-      ast = assert (cell\match str), "failed to parse: #{str}"
+      ast = assert (program\match str), "failed to parse"
       result = ast\eval scope
       result\const!
 }
diff --git a/core/registry.moon b/core/registry.moon
index 1183a0d..332c9e1 100644
--- a/core/registry.moon
+++ b/core/registry.moon
@@ -5,6 +5,7 @@
 
 import Value from require 'core.value'
 import Result from require 'core.result'
+import Error from require 'core.error'
 
 unpack or= table.unpack
 
@@ -25,7 +26,8 @@ class Registry
   -- @tparam[default=false] boolean ignore_dup ignore duplicate registrations
   register: (index, expr, ignore_dup=false) =>
     L\trace "reg: setting #{index} to #{expr}"
-    assert not @map[index] or ignore_dup, "duplicate tags with index #{index}!"
+    if not ignore_dup and @map[index]
+      error Error 'tag', "duplicate tags [#{index}]!"
     @map[index] = expr
 
   --- request identity and registration for blank tag.
diff --git a/core/scope.moon b/core/scope.moon
index f3699d7..37a1ba3 100644
--- a/core/scope.moon
+++ b/core/scope.moon
@@ -4,6 +4,7 @@
 -- @classmod Scope
 import Value from require 'core.value'
 import Result from require 'core.result'
+import Error from require 'core.error'
 
 class Scope
 --- members
@@ -26,33 +27,38 @@ class Scope
   set: (key, val) =>
     L\trace "setting #{key} = #{val} in #{@}"
     assert val.__class == Result, "expected #{key}=#{val} to be Result"
-    assert not @values[key], "cannot redefine symbol #{key}!"
+    assert val.value, Error 'type', "cannot define symbol to nil"
+    assert not @values[key], Error 'type', "cannot redefine symbol '#{key}'!"
     @values[key] = val
 
   recurse: (key) =>
     parent = if key\match '^%*.*%*$' then @dynamic_parent else @parent
     parent or= @parent
-    return parent and L\push parent\get, key
+    if parent
+      L\push parent\get, key
+    else
+      error Error 'reference', "undefined symbol '#{key}'"
 
   --- resolve a key in this Scope.
   --
   -- @tparam string key the key to resolve
-  -- @tparam[opt] string prefix a prefix (for internal use with nested scopes)
   -- @treturn ?Result the value of the definition that was found, or `nil`
-  get: (key, prefix='') =>
+  get: (key) =>
     L\debug "checking for #{key} in #{@}"
     if val = @values[key]
       L\trace "found #{val} in #{@}"
       return val
 
     start, rest = key\match '^(.-)/(.+)'
-
     if not start
       return @recurse key
 
     child = @get start
-    assert child and child.value.type == 'scope', "#{start} is not a scope (looking for #{key})"
-    child.value\unwrap!\get rest, "#{prefix}#{start}/"
+    if not child
+      error Error 'reference', "undefined symbol '#{start}'"
+    if child\type! != 'scope'
+      error Error 'reference', "'#{start}' is not a scope"
+    child.value!\get rest, while_msg
 
   --- copy definitions from another scope.
   --
diff --git a/core/value.moon b/core/value.moon
index da7f6d0..bdc4b39 100644
--- a/core/value.moon
+++ b/core/value.moon
@@ -107,7 +107,7 @@ class Value
       when 'num', 'str'
         Result value: @
       when 'sym'
-        assert (scope\get @value), Error 'reference', "undefined symbol '#{@value}'"
+        Error.wrap "resolving symbol '#{@value}'", scope\get, @value
       else
         error "cannot evaluate #{@}"