javax0.jamal.tools.Params Maven / Gradle / Ivy
package javax0.jamal.tools;
import javax0.jamal.api.BadSyntax;
import javax0.jamal.api.Identified;
import javax0.jamal.api.Input;
import javax0.jamal.api.Processor;
import javax0.jamal.tools.param.StringFetcher;
import javax0.levenshtein.Levenshtein;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import static javax0.jamal.tools.InputHandler.fetchId;
import static javax0.jamal.tools.InputHandler.firstCharIs;
import static javax0.jamal.tools.InputHandler.skip;
import static javax0.jamal.tools.InputHandler.startsWith;
/**
* Parse the start of the input for macro parameters.
*
* Multi-line built-in macros, like {@code replaceLines} or {@code trimLines} get some parameters from the first line of
* the input as well as from user defined macros. For built-in macros that need parameters this class helps with parsing
* services. The use of the class is the following:
*
{@code
* Params.using(processor).from(this).keys(Set.of(n1,h2,h3,...,hN)).parse(input)
* }
*
* This call parses the start of the input also consuming it. The parsing starts at the end of the first line. The
* processor is used to fetch values from user defined macros in case the parameter is not defined on the line. The
* parsing also checks that only {@code k1}, {@code k2}, {@code k3}, ... , {@code kn} keywords are used as parameters.
*
* For example the macro trim line can be used as the following:
*
*
{@code
* [@trimLine margin=5
* content to be trimmed
* ]
* }
*
* The implementation has to use the created {@code params} object to query the values. There are four different ways to
* access the values, as documented in the JavaDoc of the public methods.
*
* A parameter can present more than one time on the parsed line. In that case it is possible to query more values as
* list. If multiple values are present then calling the single value return will throw an exception.
*
* If a key is present on the input then the user defined macro of the same name is not used as value source.
*/
public class Params {
public static class ExtraParams {
private final Map> params = new HashMap<>();
}
public interface Param {
String[] keys();
void copy(Param p);
void inject(Processor processor, String macroName);
void set(String value);
Param orElse(String i);
Param orElseNull();
Param orElseInt(int i);
Param as(Function converter);
Param asPattern();
Param asType(Class type);
Param as(Class klass, Function converter);
Param asInt();
Param asBoolean();
Param asString();
Param> asList();
Param> asList(Class k);
T get() throws BadSyntax;
boolean is() throws BadSyntax;
boolean isPresent() throws BadSyntax;
/**
* @return the name, which was actually used for the parameter. It is the same string as the name of the
* parameter or one of the aliases.
*
* If the parameter is multi-values then the name used the last time will be returned.
*/
String name();
/**
* Set the name of the parameter, which was used. This is the original name of the parameter or one of the
* aliases. This value can be queried later calling {@link #name()}.
*
* @param id the string that was used as the parameter name/id
*/
void setName(String id);
}
private final Processor processor;
private final Map> holders = new HashMap<>();
private ExtraParams extraParams = null;
private String macroName = null;
// The character that signals the end of the parameters
// by default it is `\n` which means that the parameters are occupying the first line
// new-line, when processing parameters can also be escaped
// many times this character is ')', for core macros ']'
private Character terminal = '\n';
// The character that starts the parameters
// by default there is no such character, parameters just start on the input
// in some cases this is '(', for core macros it is '['
private Character start = null;
private static class BadKey extends BadSyntax {
final String key;
BadKey(String key, String message) {
super(message);
this.key = key;
}
}
private Params(Processor processor) {
this.processor = processor;
}
/**
* Call this static method as the first in the chain to get an uninitialized params builder structure.
*
* @param processor the processor which is used to access user defined macros when querying data
* @return a new uninitialized object needing parsing
*/
public static Params using(Processor processor) {
return new Params(processor);
}
/**
* This method identifies the macro that uses the services of the class. Only the name of the macro is used for
* error reporting purposes. The format of the use of this method is usually {@code from(this)}.
*
* @param macro the macro that is the caller object of this method
* @return {@code this} for chaining
*/
public Params from(Identified macro) {
macroName = macro.getId();
return this;
}
public Params between(String seps) {
Objects.requireNonNull(seps);
if (seps.length() != 2) {
throw new IllegalArgumentException("The argument to method 'between()' has to be a 2-character string. It was '" + seps + "'");
}
this.start = seps.charAt(0);
this.terminal = seps.charAt(1);
return this;
}
public Params startWith(char start) {
this.start = start;
return this;
}
public Params endWith(char terminal) {
this.terminal = terminal;
return this;
}
public Params tillEnd() {
this.terminal = null;
return this;
}
/**
* Specify the parameter holders and also an extra parameter holders in case there is a parameter, which is not used
* by this macro. These extra parameters may be passed to another marco that this macro may invoke and then that
* macro, instead of the {@link #parse(Input)} method will invoke the {@link #parse(ExtraParams)} methods.
*
* @param extraParams the holder for the extra parameters. It has to be a variable, as it will be passed on to the
* next macro in the chain. It can be created as {@code new Params.ExtraParams()}
* @param holders the parameter holders
* @return {@code this}
*/
public Params keys(ExtraParams extraParams, Param... holders) {
this.extraParams = extraParams;
return keys(holders);
}
/**
* Specify the parameter holders. When the parsing works it stores the values parsed into these parameter holders.
* When there is a parameter for which there is no holder an error occurs.
*
* @param holders the parameter holders
* @return {@code this}
*/
public Params keys(Param... holders) {
for (final var holder : holders) {
for (final var key : holder.keys()) {
if (key != null && this.holders.containsKey(key)) {
throw new IllegalArgumentException(
"The key '" + key + "' is used multiple times in macro '" + macroName + "'");
}
if (key != null) {
this.holders.put(key, holder);
}
}
}
return this;
}
/**
* Specify the keys that can be used to specify the value. There can be aliases. The first value is the one that can
* also be used as a macro name, the rests are alias. If the first value is null then no macro can define the value
* for this parameter.
*
* @param key the array of key and aliases
* @param the type of the parameter, can be {@code Integer}, {@code String} or {@code Boolean}
* @return a new holder
*/
public static Param holder(String... key) {
Objects.requireNonNull(key);
if (key.length == 0 || (key.length == 1 && key[0] == null)) {
throw new IllegalArgumentException("Parameter holder has to have at least one name.");
}
for (int i = 1; i < key.length; i++) {
if (key[i] == null) { // key[0] may be null, that is OK, no macro can define the parameter
throw new IllegalArgumentException("Parameter alias names must not be null.");
}
}
return new javax0.jamal.tools.param.Param<>(key);
}
/**
* Parse the input and collect the parameters in a map. The characters parsed are consumed from the input including
* the last new-line or other specified terminating character.
*
* The parameters have the format
*
{@code
* key=value
* key="value"
* key="""value"""
* key
* }
*
* When the string starts with {@code """} it is a multi-line string. In this case the parsing does not stop at the
* new line, which is inside the string.
*
* New-line characters can als be escaped using a {@code \} character right before the new line outside of strings.
* This can be used to increase the readability of the code in case there are many parameters for the macro.
*
* String parsing implements all Java string features, including all escape sequences, octal number and unicode
* escape sequences.
*
* @param input the input that starts with the parameters
* @throws BadSyntax in many cases.
*
* - if a string is not terminated till the end of the input
* - if a {@code "} separated string is not terminated till the end of the first line
* - if there is a parameter, which is not listed in the keys
*
*/
public void parse(Input input) throws BadSyntax {
try {
if (extraParams == null) {
parse(input, (id, param) -> {
holders.get(id).set(param);
holders.get(id).setName(id);
}, holders::containsKey);
} else {
parse(input, (id, param) -> {
getHolder(id).set(param);
getHolder(id).setName(id);
}, (id) -> true);
}
} catch (BadKey e) {
final var suggestions = suggest(e.key, holders.keySet());
throw throwExceptionWithSuggestions(suggestions, e);
}
}
private Params.Param getHolder(final String id) {
return holders.computeIfAbsent(id,
(xId -> extraParams.params.computeIfAbsent(xId,
javax0.jamal.tools.param.Param::new)));
}
public void parse(ExtraParams extraParams) throws BadSyntax {
parse();
for (final var e : extraParams.params.entrySet()) {
final var id = e.getKey();
if (!holders.containsKey(id)) {
if (this.extraParams != null) {
getHolder(id).copy(e.getValue());
} else {
final var suggestions = suggest(id, holders.keySet());
throw throwExceptionWithSuggestions(suggestions,
new BadKey(e.getKey(), "The key '" + id + "' is not used by the macro '" + macroName + "'."));
}
}
holders.get(e.getKey()).copy(e.getValue());
}
}
/**
* This is a general purpose version of the parameter handling. This method parses the parameters and fills them
* into a LinkedHashMap. It is guaranteed that the keys are in the same order as they are in the input.
*
* This version of the parsing was added to support parameter parsing of XML tag attributes, which is the same
* syntax as the parameters. In this version the parsed values are returned as a map and the holders of the
* {@code Params} are not used.
*
* @param input the input that contains the parameters
* @return the linked hash map with the parameters
* @throws BadSyntax in the same cases as {@link #parse(Input)}
*/
public LinkedHashMap fetchParameters(Input input) throws BadSyntax {
final var parameters = new LinkedHashMap();
try {
parse(input, parameters::put, id -> !parameters.containsKey(id));
} catch (BadKey e) {
final var suggestions = suggest(e.key, parameters.keySet());
throw throwExceptionWithSuggestions(suggestions, e);
}
return parameters;
}
/**
* Throws a BadSyntax exception fetching the erroneous key from the {@link BadKey} exception and composing a
* suggestion set.
*
* If the suggestions set is empty, the exception is thrown without suggestions.
*
* @param suggestions the set of suggestions
* @param e the BadKey exception
* @return does not return, but declared to return a BadSyntax exception, so that the caller can "throw" it, and
* it helps the data flow analysis of the compiler.
* @throws BadSyntax is the composed exception
*/
private BadSyntax throwExceptionWithSuggestions(final Set suggestions, final BadKey e) throws BadSyntax {
if (suggestions.isEmpty()) {
throw e;
} else {
throw new BadSyntax("The key '"
+ e.key
+ "' is not used by the macro '" + macroName
+ "'. Did you mean "
+ suggestions
.stream()
.map(s -> "'" + s + "'")
.collect(Collectors.joining(", ")) + "?");
}
}
/**
* Get the suggestions that are similar to the given key.
*
* @param spelling the misspelled key
* @param keys the set of the valid keys
* @return the set of suggestions
*/
private Set suggest(String spelling, Set keys) {
final Set suggestions = new HashSet<>();
int minDistance = 3;
for (String key : keys) {
final int distance = Levenshtein.distance(key, spelling);
if (distance < minDistance) {
minDistance = distance;
suggestions.clear();
}
if (distance <= minDistance) {
suggestions.add(key);
}
}
return suggestions;
}
public void parse(Input input, BiConsumer store, Predicate valid) throws BadSyntax {
parse();
skipStartingSpacesAndEscapedTerminal(input);
if (start != null) {
if (firstCharIs(input, start)) {
skip(input, 1);
} else {
return;
}
}
while ((terminal == null || !firstCharIs(input, terminal)) && input.length() > 0) {
if (terminal != null && firstCharIs(input, terminal)) {
break;
}
skipSpacesAndEscapedTerminal(input);
final var id = fetchId(input);
if (!valid.test(id)) {
throw new BadKey(id, "The key '" + id + "' is not used by the macro '" + macroName + "'.");
}
final String param;
skipSpacesAndEscapedTerminal(input);
if (firstCharIs(input, '=')) {
skip(input, 1);
skipSpacesAndEscapedTerminal(input);
param = StringFetcher.getString(input, terminal);
} else {
param = "true";
}
store.accept(id, param);
skipSpacesAndEscapedTerminal(input);
}
skip(input, 1);
}
public void parse() {
for (final var holder : holders.values()) {
holder.inject(processor, macroName);
}
}
/**
* Skip all the characters for which the {@code skipper} predicate returns true.
* If the next character after all the skipped characters are {@code \} and {@code \n} (escaped new line) then
* step over these and start the skipping again.
*
* Skipping a character means deleting it from the front of theinput.
*
* @param input to input to delete the characters from
* @param skipper the predicate deciding if a chavater is to be skipped or not
*/
private static void skipper(Input input, Predicate skipper) {
while (true) {
while (skipper.test(input)) {
input.delete(1);
}
if (startsWith(input, "\\\n") != -1) {
skip(input, 2);
} else {
return;
}
}
}
/**
* Skip all characters, also new line characters, except when the terminal character is newline. In that case
* the terminal character (which is a new line) stops the skipping. This method is used to eat the extra characters
* between parameters.
*
* @param input the input that contains the next parameters with spaces optionally in front of them
*/
private void skipSpacesAndEscapedTerminal(Input input) {
skipper(input, i -> i.length() > 0 && Character.isWhitespace(i.charAt(0)) && !Objects.equals(i.charAt(0), terminal));
}
/**
* Skip all the white space characters except new line. This method is invoked before the parameters.
* An \ escaped newline character does not stop the skipping.
*
* @param input that contains the parameters with spaces optionally in front of them
*/
private void skipStartingSpacesAndEscapedTerminal(Input input) {
skipper(input, i -> i.length() > 0 && Character.isWhitespace(i.charAt(0)) && !Objects.equals(i.charAt(0), '\n'));
}
}