diff options
Diffstat (limited to 'lib/control_flow.nom')
| -rw-r--r-- | lib/control_flow.nom | 49 |
1 files changed, 43 insertions, 6 deletions
diff --git a/lib/control_flow.nom b/lib/control_flow.nom index aeb63ef..2d1a6a4 100644 --- a/lib/control_flow.nom +++ b/lib/control_flow.nom @@ -218,11 +218,48 @@ compile [when %branch_value == ? %body] to code: |end --when == ? %result -# With statement -compile [with %thing = %value %action] to code: ".." +# Try/except +compile [..] + try %action and if it succeeds %success or if it fails %fallback + try %action and if it fails %fallback or if it succeeds %success +..to code: ".." |do - | local old_value = \(%thing as lua); - | \(%thing as lua) = \(%value as lua); - | \(%action as lua statements); - | \(%thing as lua) = old_value; + | local fell_through = false; + | local ok, ret1, ret2 = pcall(function(nomsu, vars) + | \(%action as lua statements) + | fell_through = true; + | end, nomsu, vars); + | if ok then + | \(%success as lua statements) + | end + | if not ok then + | \(%fallback as lua statements) + | elseif not fell_through then + | return ret1, ret2; + | end |end +parse [try %action] as: + try %action and if it succeeds {pass} or if it fails {pass} +parse [try %action and if it fails %fallback] as: + try %action and if it succeeds {pass} or if it fails %fallback +parse [try %action and if it succeeds %success] as: + try %action and if it succeeds %success or if it fails {pass} + +# Do/finally: +compile [do %action then always %final_action] to code: ".." + |do + | local fell_through = false; + | local ok, ret1, ret2 = pcall(function(nomsu, vars) + | \(%action as lua statements) + | fell_through = true; + | end, nomsu, vars); + | local ok2, _ = pcall(function(nomsu, vars) + | \(%final_action as lua statements) + | end, nomsu, vars); + | if not ok then nomsu:error(ret1); end + | if not ok2 then nomsu:error(ret2); end + | if not fell_through then + | return ret1, ret2; + | end + |end + |