Misc changes, including text indented interpolations are now indented

relative to the text, not the opening '("', code objects can now remove
all free vars, the REPL uses global vars. Error API is changing a bit.

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)