Strict setting controls \newline display-mode behavior; fix MacroExpander space handling (#1314)

* Strict setting controls \newline display-mode behavior

* Bug-fix space handling in macros

Whitespace after a \controlWord is now handled within the lexer, not by the
MacroExpander.  This way, \\ expanding to \newline doesn't accidentally
cause spaces to get consumed.

* Rename nonstrict -> reportNonstrict; strictBehavior -> useStrictBehavior

* Second category of errorCodes

test/errors-spec.js

@@ -60,12 +60,12 @@ describe("Parser:", function() {
         it("rejects repeated infix operators", function() {
             expect("1\\over 2\\over 3").toFailWithParseError(
                    "only one infix operator per group at position 9: " +
-                   "1\\over 2\\̲o̲v̲e̲r̲ 3");
+                   "1\\over 2\\̲o̲v̲e̲r̲ ̲3");
         });
         it("rejects conflicting infix operators", function() {
             expect("1\\over 2\\choose 3").toFailWithParseError(
                    "only one infix operator per group at position 9: " +
-                   "1\\over 2\\̲c̲h̲o̲o̲s̲e̲ 3");
+                   "1\\over 2\\̲c̲h̲o̲o̲s̲e̲ ̲3");
         });
     });
 

test/katex-spec.js

@@ -181,7 +181,7 @@ beforeEach(function() {
             expect(actual).toParse(usedSettings);
 
             try {
-                _getBuilt(actual, settings);
+                _getBuilt(actual, usedSettings);
             } catch (e) {
                 result.pass = false;
                 if (e instanceof ParseError) {
@@ -196,6 +196,31 @@ beforeEach(function() {
             return result;
         },
 
+        toNotBuild: function(actual, settings) {
+            const usedSettings = settings ? settings : defaultSettings;
+
+            const result = {
+                pass: false,
+                message: () => "Expected '" + actual + "' to fail " +
+                    "building, but it succeeded",
+            };
+
+            try {
+                _getBuilt(actual, usedSettings);
+            } catch (e) {
+                if (e instanceof ParseError) {
+                    result.pass = true;
+                    result.message = () => "'" + actual + "' correctly " +
+                        "didn't build with error: " + e.message;
+                } else {
+                    result.message = () => "'" + actual + "' failed " +
+                        "building with unknown error: " + e.message;
+                }
+            }
+
+            return result;
+        },
+
         toParseLike: function(actual, expected, settings) {
             const usedSettings = settings ? settings : defaultSettings;
 
@@ -2719,6 +2744,10 @@ describe("A macro expander", function() {
         compareParseTree("\\text{\\foo }", "\\text{}", {"\\foo": "\\relax"});
     });
 
+    it("should not consume spaces after control-word expansion", function() {
+        compareParseTree("\\text{\\\\ }", "\\text{ }", {"\\\\": "\\relax"});
+    });
+
     it("should consume spaces after \\relax", function() {
         compareParseTree("\\text{\\relax }", "\\text{}");
     });
@@ -3133,7 +3162,7 @@ describe("Newlines via \\\\ and \\newline", function() {
     });
 
     it("should not allow \\cr at top level", () => {
-        expect("hello \\cr world").toNotParse();
+        expect("hello \\cr world").toNotBuild();
     });
 });
 
@@ -3186,6 +3215,11 @@ describe("strict setting", function() {
         expect("\\text{é試}").toParse(new Settings({strict: true}));
         expect("\\text{é試}").toParse();
     });
+
+    it("should warn about top-level \\newline in display mode", () => {
+        expect("x\\\\y").toWarn(new Settings({displayMode: true}));
+        expect("x\\\\y").toParse(new Settings({displayMode: false}));
+    });
 });
 
 describe("Internal __* interface", function() {