diff --git a/src/environments.js b/src/environments.js
index ff294ca7a..c589d752b 100644
--- a/src/environments.js
+++ b/src/environments.js
@@ -38,32 +38,54 @@ function parseArray(parser, pos, mode, result) {
 }
 
 /*
- * An environment definition is very similar to a function definition.
- * Each element of the following array may contain
- *  - names: The names associated with a function. This can be used to
- *           share one implementation between several similar environments.
+ * An environment definition is very similar to a function definition:
+ * it is declared with a name or a list of names, a set of properties
+ * and a handler containing the actual implementation.
+ *
+ * The properties include:
  *  - numArgs: The number of arguments after the \begin{name} function.
  *  - argTypes: (optional) Just like for a function
  *  - allowedInText: (optional) Whether or not the environment is allowed inside
  *                   text mode (default false) (not enforced yet)
  *  - numOptionalArgs: (optional) Just like for a function
- *  - handler: The function that is called to handle this environment.
- *             It will receive the following arguments:
+ * A bare number instead of that object indicates the numArgs value.
+ *
+ * The handler function will receive the following arguments:
  *             - pos: the current position of the parser.
  *             - mode: the current parsing mode.
  *             - envName: the name of the environment, one of the listed names.
  *             - [args]: the arguments passed to \begin.
  *             - positions: the positions associated with these arguments.
+ * The handler is called with `this` referring to the parser.
+ * It must return a ParseResult.
  */
 
-var environmentDefinitions = [
+function defineEnvironment(names, props, handler) {
+    if (typeof names === "string") {
+        names = [names];
+    }
+    if (typeof props === "number") {
+        props = { numArgs: props };
+    }
+    // Set default values of environments
+    var data = {
+        numArgs: props.numArgs || 0,
+        argTypes: props.argTypes,
+        greediness: 1,
+        allowedInText: !!props.allowedInText,
+        numOptionalArgs: props.numOptionalArgs || 0,
+        handler: handler
+    };
+    for (var i = 0; i < names.length; ++i) {
+        module.exports[names[i]] = data;
+    }
+}
 
     // Arrays are part of LaTeX, defined in lttab.dtx so its documentation
     // is part of the source2e.pdf file of LaTeX2e source documentation.
-    {
-        names: ["array"],
-        numArgs: 1,
-        handler: function(pos, mode, envName, colalign, positions) {
+    defineEnvironment("array", {
+        numArgs: 1
+    }, function(pos, mode, envName, colalign, positions) {
             var parser = this;
             colalign = colalign.value.map ? colalign.value : [colalign];
             var cols = colalign.map(function(node) {
@@ -90,21 +112,19 @@ var environmentDefinitions = [
             };
             res = parseArray(parser, pos, mode, res);
             return res;
-        }
-    },
+        });
 
     // The matrix environments of amsmath builds on the array environment
     // of LaTeX, which is discussed above.
-    {
-        names: [
+    defineEnvironment([
             "matrix",
             "pmatrix",
             "bmatrix",
             "Bmatrix",
             "vmatrix",
             "Vmatrix"
-        ],
-        handler: function(pos, mode, envName) {
+        ], {
+    }, function(pos, mode, envName) {
             var delimiters = {
                 "matrix": null,
                 "pmatrix": ["(", ")"],
@@ -126,15 +146,13 @@ var environmentDefinitions = [
                 }, mode);
             }
             return res;
-        }
-    },
+        });
 
     // A cases environment (in amsmath.sty) is almost equivalent to
     // \def\arraystretch{1.2}%
     // \left\{\begin{array}{@{}l@{\quad}l@{}} … \end{array}\right.
-    {
-        names: ["cases"],
-        handler: function(pos, mode, envName) {
+    defineEnvironment("cases", {
+    }, function(pos, mode, envName) {
             var res = {
                 type: "array",
                 arraystretch: 1.2,
@@ -157,22 +175,4 @@ var environmentDefinitions = [
                 right: "."
             }, mode);
             return res;
-        }
-    }
-];
-
-module.exports = (function() {
-    // nested function so we don't leak i and j into the module scope
-    var exports = {};
-    for (var i = 0; i < environmentDefinitions.length; ++i) {
-        var def = environmentDefinitions[i];
-        def.greediness = 1;
-        def.allowedInText = !!def.allowedInText;
-        def.numArgs = def.numArgs || 0;
-        def.numOptionalArgs = def.numOptionalArgs || 0;
-        for (var j = 0; j < def.names.length; ++j) {
-            exports[def.names[j]] = def;
-        }
-    }
-    return exports;
-})();
+        });