Current state of mal for Clojure West lighting talk.

1 files changed, 127 insertions, 0 deletions

diff --git a/js/reader.js b/js/reader.js
new file mode 100644
index 0000000..da51088
--- /dev/null
+++ b/js/reader.js
@@ -0,0 +1,127 @@
+// Node vs browser behavior
+var reader = {};
+if (typeof module !== 'undefined') {
+    var types = require('./types');
+} else {
+    var exports = reader;
+}
+
+function Reader(tokens) {
+    // copy
+    this.tokens = tokens.map(function (a) { return a; });
+    this.position = 0;
+}
+Reader.prototype.next = function() { return this.tokens[this.position++]; }
+Reader.prototype.peek = function() { return this.tokens[this.position]; }
+
+function tokenize(str) {
+    var re = /[\s,]*(~@|[\[\]{}()'`~^@]|"(?:\\.|[^\\"])*"|;.*|[^\s\[\]{}('"`,;)]*)/g;
+    var results = [];
+    while ((match = re.exec(str)[1]) != '') {
+        if (match[0] === ';') { continue; }
+        results.push(match);
+    }
+    return results;
+}
+
+function read_atom (reader) {
+    var token = reader.next();
+    //console.log("read_atom:", token);
+    if (token.match(/^-?[0-9]+$/)) {
+        return parseInt(token,10)        // integer
+    } else if (token.match(/^-?[0-9][0-9.]*$/)) {
+        return parseFloat(token,10);     // float
+    } else if (token[0] === "\"") {
+        return token.slice(1,token.length-1).replace(/\\"/g, '"'); // string
+    } else if (token === "nil") {
+        return null;
+    } else if (token === "true") {
+        return true;
+    } else if (token === "false") {
+        return false;
+    } else {
+        return types.symbol(token); // symbol
+    }
+}
+
+// read list of tokens
+function read_list(reader, start, end) {
+    start = start || '(';
+    end = end || ')';
+    var ast = [];
+    var token = reader.next();
+    if (token !== start) {
+        throw new Error("expected '" + start + "'");
+    }
+    while ((token = reader.peek()) !== end) {
+        if (!token) {
+            throw new Error("expected '" + end + "', got EOF");
+        }
+        ast.push(read_form(reader));
+    }
+    reader.next();
+    return ast;
+}
+
+// read vector of tokens
+function read_vector(reader) {
+    var lst = read_list(reader, '[', ']');
+    return types.vector.apply(types.vector, lst);
+}
+
+// read hash-map key/value pairs
+function read_hash_map(reader) {
+    var lst = read_list(reader, '{', '}');
+    return types.hash_map.apply(types.hash_map, lst);
+}
+
+function read_form(reader) {
+    var token = reader.peek();
+    switch (token) {
+    // reader macros/transforms
+    case ';': return null; // Ignore comments
+    case '\'': reader.next();
+               return [types.symbol('quote'), read_form(reader)];
+    case '`': reader.next();
+              return [types.symbol('quasiquote'), read_form(reader)];
+    case '~': reader.next();
+              return [types.symbol('unquote'), read_form(reader)];
+    case '~@': reader.next();
+               return [types.symbol('splice-unquote'), read_form(reader)];
+    case '^': reader.next();
+              var meta = read_form(reader);
+              return [types.symbol('with-meta'), read_form(reader), meta];
+    case '@': reader.next();
+              return [types.symbol('deref'), read_form(reader)];
+
+    // list
+    case ')': throw new Error("unexpected ')'");
+    case '(': return read_list(reader);
+
+    // vector
+    case ']': throw new Error("unexpected ']'");
+    case '[': return read_vector(reader);
+
+    // hash-map
+    case '}': throw new Error("unexpected '}'");
+    case '{': return read_hash_map(reader);
+
+    // atom
+    default:  return read_atom(reader);
+    }
+}
+
+function BlankException(msg) {
+}
+
+function read_str(str) {
+    var tokens = tokenize(str);
+    if (tokens.length === 0) { throw new BlankException(); }
+    return read_form(new Reader(tokens))
+}
+
+exports.Reader = reader.Reader = Reader;
+exports.BlankException = reader.BlankException = BlankException;
+exports.tokenize = reader.tokenize = tokenize;
+exports.read_form = reader.read_form = read_form;
+exports.read_str = reader.read_str = read_str;