1 files changed, 38 insertions, 0 deletions

@@ -7,6 +7,12 @@ local pop = require("util").pop
 
 local pp = require("pp").pp
 
+-- TODO:
+-- - string reading
+-- - # syntax
+-- - comments
+-- - probably more
+
 function m.inport (source, kind)
         -- KIND can be one of "file", "string"; defaults to "file"
         -- SOURCE is the name of the file or the string to read, or nil; if nil,
@@ -85,6 +91,18 @@ end
 m.readtable = {
         ["("] = function (cs) return pop(cs), "open", cs end,
         [")"] = function (cs) return pop(cs), "close", cs end,
+        ["'"] = function (cs) return pop(cs), "quote", cs end,
+        ["`"] = function (cs) return pop(cs), "quote", cs end,
+        [","] =
+                function (cs)
+                        pop(cs) -- remove ','
+                        if cs[1] == "@" then
+                                pop(cs) -- remove '@'
+                                return ",@", "quote", cs
+                        else
+                                return ",", "quote", cs
+                        end
+                end,
 }
 
 -- Return an iterator over a character table, so you can do:
@@ -131,6 +149,24 @@ function m.readchar (port)
         end
 end
 
+m.readmacros = {
+        quote =
+                function (tok, toktype, port)
+                        local qs = {
+                                ["'"] = "quote",
+                                ["`"] = "quasiquote",
+                                [","] = "unquote",
+                                [",@"] = "unquote-splicing",
+                        }
+                        if not qs[tok] then
+                                error(string.format("Bad quote: '%s'\n", tok))
+                        end
+                        local Q = {qs[tok]}
+                        table.insert(Q, m.read(port))
+                        return t.list(Q)
+                end,
+}
+
 function m.read (port)
         local function read_ahead (tok, toktype)
                 if not tok then error("Unexpected EOF") end
@@ -151,6 +187,8 @@ function m.read (port)
                         end
                 elseif toktype == "close" then
                         error("Unexpected ')'")
+                elseif m.readmacros[toktype] then
+                        return m.readmacros[toktype](tok, toktype, port)
                 else return tok
                 end
         end