Parser reorganization, parsing lenience++.
Reorganized the parser as a proper class so that I could easily reenter it to
deal with things like optional second open and close tag characters. In the
process, made the parser simply pass through certain kinds of malformed input
as text.
I hope to go further in this regard, avoiding parse exceptions in favor of
simply showing the user the malformed output unsubstituted. It's just as easy
to see "{{broken blah blah" in ones result template as it is to read exception
messages, and apps that wish to use JMustache for things like end-user
templates will find this much more agreeable.
This commit is contained in:
Michael Bayne
@@ -141,46 +141,111 @@ public class Mustache
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*/
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protected static Template compile (Reader source, Compiler compiler)
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{
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// a hand-rolled parser; whee!
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Accumulator accum = new Accumulator(compiler);
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Delims delims = new Delims();
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Accumulator accum = new Parser(compiler).parse(source);
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return new Template(accum.finish(), compiler);
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}
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private Mustache () {} // no instantiateski
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protected static void restoreStartTag (StringBuilder text, Delims starts)
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{
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text.insert(0, starts.start1);
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if (starts.start2 != NO_CHAR) {
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text.insert(1, starts.start2);
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}
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}
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protected static String escapeHTML (String text)
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{
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for (String[] escape : ATTR_ESCAPES) {
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text = text.replace(escape[0], escape[1]);
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}
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return text;
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}
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protected static boolean allowsWhitespace (char typeChar)
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{
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return (typeChar == '=') || // change delimiters
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(typeChar == '!'); // comment
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}
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protected static final int TEXT = 0;
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protected static final int MATCHING_START = 1;
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protected static final int MATCHING_END = 2;
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protected static final int TAG = 3;
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// a hand-rolled parser; whee!
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protected static class Parser {
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final Delims delims = new Delims();
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final StringBuilder text = new StringBuilder();
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Reader source;
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Accumulator accum;
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int state = TEXT;
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StringBuilder text = new StringBuilder();
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int line = 1;
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boolean skipNewline = false;
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while (true) {
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char c;
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try {
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int v = source.read();
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if (v == -1) {
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break;
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}
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c = (char)v;
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} catch (IOException e) {
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throw new MustacheException(e);
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}
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public Parser (Compiler compiler) {
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this.accum = new Accumulator(compiler);
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}
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if (c == '\n') {
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line++;
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// if we just parsed an open section or close section task, we'll skip the first
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// newline character following it, if desired; TODO: handle CR, sigh
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if (skipNewline) {
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public Accumulator parse (Reader source) {
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this.source = source;
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while (true) {
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char c;
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try {
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int v = source.read();
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if (v == -1) {
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break;
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}
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c = (char)v;
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} catch (IOException e) {
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throw new MustacheException(e);
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}
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if (c == '\n') {
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line++;
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// if we just parsed an open section or close section task, we'll skip the first
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// newline character following it, if desired; TODO: handle CR, sigh
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if (skipNewline) {
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skipNewline = false;
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continue;
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}
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} else {
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skipNewline = false;
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continue;
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}
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} else {
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skipNewline = false;
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parseChar(c);
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}
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// accumulate any trailing text
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switch (state) {
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case TAG:
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restoreStartTag(text, delims);
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break;
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case MATCHING_END:
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restoreStartTag(text, delims);
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text.append(delims.end1);
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break;
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case MATCHING_START:
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text.append(delims.start1);
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break;
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// case TEXT: // do nothing
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}
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accum.addTextSegment(text);
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return accum;
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}
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protected void parseChar (char c) {
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switch (state) {
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case TEXT:
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if (c == delims.start1) {
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state = MATCHING_START;
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if (delims.start2 == NO_CHAR) {
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accum.addTextSegment(text);
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state = TAG;
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} else {
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state = MATCHING_START;
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parseChar(NO_CHAR);
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}
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} else {
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text.append(c);
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@@ -193,28 +258,31 @@ public class Mustache
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state = TAG;
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} else {
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text.append(delims.start1);
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if (c != delims.start1) {
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text.append(c);
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state = TEXT;
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}
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state = TEXT;
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parseChar(c);
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}
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break;
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case TAG:
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if (c == delims.end1) {
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state = MATCHING_END;
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if (delims.end2 == NO_CHAR) {
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if (text.charAt(0) == '=') {
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delims.updateDelims(text.substring(1, text.length()-1));
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text.setLength(0);
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} else {
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sanityCheckTag(text, line, delims.start1, delims.start2);
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accum = accum.addTagSegment(text, line);
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skipNewline = accum.skipNewline();
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}
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state = TEXT;
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} else {
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state = MATCHING_END;
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parseChar(NO_CHAR);
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}
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} else if (c == delims.start1 && text.length() > 0) {
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// if we've already matched some tag characters and we see a new start tag
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// character (e.g. "{{foo {" but not "{{{"), treat the already matched text as
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// plain text and start matching a new tag from this point
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restoreStartTag(text, delims);
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accum.addTextSegment(text);
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if (delims.start2 == NO_CHAR) {
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accum.addTextSegment(text);
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state = TAG;
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} else {
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state = MATCHING_START;
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}
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} else {
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text.append(c);
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}
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@@ -244,69 +312,21 @@ public class Mustache
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text.replace(0, 1, "&");
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}
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// process the tag between the mustaches
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sanityCheckTag(text, line, delims.start1, delims.start2);
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accum = accum.addTagSegment(text, line);
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skipNewline = accum.skipNewline();
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}
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state = TEXT;
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} else {
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text.append(delims.end1);
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if (c != delims.end1) {
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text.append(c);
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state = TAG;
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}
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state = TAG;
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parseChar(c);
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}
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break;
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}
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}
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// accumulate any trailing text
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switch (state) {
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case TEXT:
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accum.addTextSegment(text);
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break;
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case MATCHING_START:
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text.append(delims.start1);
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accum.addTextSegment(text);
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break;
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case MATCHING_END:
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text.append(delims.end1);
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accum.addTextSegment(text);
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break;
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case TAG:
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throw new MustacheParseException("Template ended while parsing a tag: " + text);
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}
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return new Template(accum.finish(), compiler);
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}
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private Mustache () {} // no instantiateski
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protected static void sanityCheckTag (StringBuilder accum, int line, char start1, char start2)
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{
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for (int ii = 0, ll = accum.length(); ii < ll; ii++) {
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if (accum.charAt(ii) == start1) {
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if (start2 == NO_CHAR || (ii < ll-1 && accum.charAt(ii+1) == start2)) {
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throw new MustacheParseException("Tag contains start tag delimiter, probably " +
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"missing close delimiter '" + accum + "'", line);
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}
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}
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}
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}
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protected static String escapeHTML (String text)
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{
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for (String[] escape : ATTR_ESCAPES) {
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text = text.replace(escape[0], escape[1]);
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}
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return text;
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}
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protected static final int TEXT = 0;
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protected static final int MATCHING_START = 1;
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protected static final int MATCHING_END = 2;
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protected static final int TAG = 3;
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protected static class Delims {
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public char start1 = '{';
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public char start2 = '{';
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@@ -205,9 +205,16 @@ public class MustacheTest
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execute(context("a", "<b>")));
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}
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@Test(expected=MustacheParseException.class)
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public void testDanglingTag () {
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Mustache.compiler().escapeHTML(true).compile("{{a").execute(context("a", "<b>"));
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@Test public void testDanglingTag () {
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test("foo{", "foo{", context("a", "<b>"));
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test("foo{{", "foo{{", context("a", "<b>"));
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test("foo{{a", "foo{{a", context("a", "<b>"));
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test("foo{{a}", "foo{{a}", context("a", "<b>"));
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}
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@Test public void testRepeatedOpenTag () {
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test("{{ funny [b] business", "{{ funny {{a}} business", context("a", "[b]"));
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test("{{ funny <b> business", "{{ funny {{{a}}} business", context("a", "<b>"));
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}
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@Test(expected=MustacheParseException.class)
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