Reorganization

1 files changed, 68 insertions, 0 deletions

@@ -0,0 +1,68 @@
+--- lam.load
+
+local m = {}
+local core = require("core")
+local eval = require("eval")
+local port = require("port")
+local read = require("read")
+local type = require("type")
+
+local function schemeprint (x)
+        -- possibly a candidate to put in a `write' library
+        if x == true then print("#t")
+        elseif x == false then print("#f")
+        elseif x == nil then return -- print("#<nil>")
+        else print(x)
+        end
+end
+
+local function handle_error (e)
+        local start = e:find(": ")
+        return e:sub(start + 2)
+end
+
+function m.load (filename, interactive)
+        -- interactive = { out = file/handle, prompt = string, }
+        local inport = port.input_port(filename)
+        if interactive then
+                io.output(interactive.out)
+                io.output():setvbuf("line")
+        else
+                io.output():setvbuf("no")
+        end
+        repeat
+                if interactive then
+                        io.stderr:write(interactive.prompt or "")
+                        io.stderr:flush()
+                end
+                -- read
+                local read_ok, form = xpcall(
+                        function () return read.read(inport) end,
+                        handle_error)
+                if form == port.eof then break end
+                if not read_ok then
+                        io.stderr:write("error (read): ", form, "\n")
+                        -- when interactive, errors should not be fatal, but
+                        -- they should be in batch mode
+                        inport:flush() -- avoid endless loop
+                        if not interactive then return nil end
+                else
+                        -- eval
+                        local eval_ok, value = xpcall(
+                                function ()
+                                        return eval.eval(form, core.environment)
+                                end,
+                                handle_error)
+                        if not eval_ok then
+                                io.stderr:write("error (eval): ", value, "\n")
+                                if not interactive then return nil end
+                        else
+                                -- print
+                                if interactive then schemeprint(value) end
+                        end
+                end
+        until value == port.eof -- loop
+end
+
+--------
+return m