implement command completion popup

tools/lammps-gui/codeeditor.cpp

@@ -15,6 +15,7 @@
 #include "lammpsgui.h"
 #include "linenumberarea.h"
 
+#include <QAbstractItemView>
 #include <QAction>
 #include <QDesktopServices>
 #include <QDragEnterEvent>
@@ -25,7 +26,9 @@
 #include <QMimeData>
 #include <QPainter>
 #include <QRegularExpression>
+#include <QScrollBar>
 #include <QSettings>
+#include <QStringListModel>
 #include <QTextBlock>
 #include <QUrl>
 
@@ -42,8 +45,8 @@ static std::vector<std::string> split_line(const std::string &text)
     std::size_t beg = 0;
     std::size_t len = 0;
     std::size_t add = 0;
-    char c          = *buf;
 
+    char c = *buf;
     while (c) { // leading whitespace
         if (c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == '\f') {
             c = *++buf;
@@ -115,7 +118,8 @@ static std::vector<std::string> split_line(const std::string &text)
     return list;
 }
 
-CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent), highlight(NO_HIGHLIGHT)
+CodeEditor::CodeEditor(QWidget *parent) :
+    QPlainTextEdit(parent), command_completer(nullptr), highlight(NO_HIGHLIGHT)
 {
     help_action = new QShortcut(QKeySequence::fromString("Ctrl+?"), parent);
     connect(help_action, &QShortcut::activated, this, &CodeEditor::get_help);
@@ -269,14 +273,64 @@ QString CodeEditor::reformatLine(const QString &line)
     return newtext;
 }
 
+void CodeEditor::setCommandList(const QStringList &words)
+{
+    delete command_completer;
+    command_completer = new QCompleter(this);
+    command_completer->setModel(new QStringListModel(words, command_completer));
+    command_completer->setCompletionMode(QCompleter::PopupCompletion);
+    command_completer->setModelSorting(QCompleter::CaseInsensitivelySortedModel);
+    command_completer->setWidget(this);
+    command_completer->setWrapAround(false);
+
+    QObject::connect(command_completer, QOverload<const QString &>::of(&QCompleter::activated),
+                     this, &CodeEditor::insertCompletedCommand);
+    reformatCurrentLine();
+}
+
 void CodeEditor::keyPressEvent(QKeyEvent *event)
 {
+    if (command_completer && command_completer->popup()->isVisible()) {
+        // The following keys are forwarded by the completer to the widget
+        switch (event->key()) {
+            case Qt::Key_Enter:
+            case Qt::Key_Return:
+            case Qt::Key_Escape:
+            case Qt::Key_Tab:
+            case Qt::Key_Backtab:
+                event->ignore();
+                return; // let the completer do default behavior
+            default:
+                break;
+        }
+    }
     if (event->key() == Qt::Key_Tab) {
         reformatCurrentLine();
         return;
     }
     if (event->key() == Qt::Key_Backtab) {
-        fprintf(stderr, "Shift + Tab key hit\n");
+        if (command_completer) {
+            auto cursor = textCursor();
+            auto line   = cursor.block().text().trimmed();
+            if (line.isEmpty()) return;
+
+            auto words = split_line(line.toStdString());
+            cursor.select(QTextCursor::WordUnderCursor);
+
+            // if on first word, try to complete command
+            if ((words.size() > 0) && (words[0] == cursor.selectedText().toStdString())) {
+                // no completion on comment lines
+                if (words[0][0] == '#') return;
+                command_completer->setCompletionPrefix(words[0].c_str());
+                auto popup = command_completer->popup();
+                QRect cr   = cursorRect();
+                cr.setWidth(popup->sizeHintForColumn(0) +
+                            popup->verticalScrollBar()->sizeHint().width());
+                popup->setAlternatingRowColors(true);
+                command_completer->setCurrentRow(0);
+                command_completer->complete(cr);
+            }
+        }
         return;
     }
     QPlainTextEdit::keyPressEvent(event);
@@ -425,6 +479,17 @@ void CodeEditor::reformatCurrentLine()
     }
 }
 
+void CodeEditor::insertCompletedCommand(const QString &completion)
+{
+    if (command_completer->widget() != this) return;
+    auto cursor = textCursor();
+    int extra   = completion.length() - command_completer->completionPrefix().length();
+    cursor.movePosition(QTextCursor::Left);
+    cursor.movePosition(QTextCursor::EndOfWord);
+    cursor.insertText(completion.right(extra));
+    setTextCursor(cursor);
+}
+
 void CodeEditor::get_help()
 {
     QString page, help;

tools/lammps-gui/codeeditor.h

@@ -14,11 +14,13 @@
 #ifndef CODEEDITOR_H
 #define CODEEDITOR_H
 
+#include <QCompleter>
 #include <QFont>
 #include <QMap>
 #include <QPlainTextEdit>
 #include <QShortcut>
 #include <QString>
+#include <QStringList>
 
 class CodeEditor : public QPlainTextEdit {
     Q_OBJECT
@@ -32,6 +34,7 @@ public:
     void setCursor(int block);
     void setHighlight(int block, bool error);
     QString reformatLine(const QString &line);
+    void setCommandList(const QStringList &words);
 
     static constexpr int NO_HIGHLIGHT = 1 << 30;
 
@@ -50,10 +53,12 @@ private slots:
     void find_help(QString &page, QString &help);
     void open_help();
     void reformatCurrentLine();
+    void insertCompletedCommand(const QString &completion);
 
 private:
     QWidget *lineNumberArea;
     QShortcut *help_action;
+    QCompleter *command_completer;
     int highlight;
 
     QMap<QString, QString> cmd_map;

tools/lammps-gui/lammps_internal_commands.txt

@@ -0,0 +1,70 @@
+clear
+echo
+if
+include
+jump
+label
+log
+next
+partition
+print
+python
+quit
+shell
+variable
+angle_coeff
+angle_style
+atom_modify
+atom_style
+bond_coeff
+bond_style
+bond_write
+boundary
+comm_modify
+comm_style
+compute
+compute_modify
+dielectric
+dihedral_coeff
+dihedral_style
+dimension
+dump
+dump_modify
+fix
+fix_modify
+group
+improper_coeff
+improper_style
+kspace_modify
+kspace_style
+labelmap
+lattice
+mass
+min_modify
+min_style
+molecule
+neigh_modify
+neighbor
+newton
+package
+pair_coeff
+pair_modify
+pair_style
+pair_write
+processors
+region
+reset_timestep
+restart
+run_style
+special_bonds
+suffix
+thermo
+thermo_modify
+thermo_style
+timestep
+timer
+uncompute
+undump
+unfix
+units
+reset_atoms

tools/lammps-gui/lammpsgui.cpp

@@ -57,6 +57,7 @@
 
 static const QString blank(" ");
 static constexpr int MAXRECENT = 5;
+static constexpr int BUFLEN = 128;
 
 // duplicate string
 static char *mystrdup(const std::string &text)
@@ -296,6 +297,25 @@ LammpsGui::LammpsGui(QWidget *parent, const char *filename) :
         setWindowTitle(QString("LAMMPS-GUI - *unknown*"));
     }
     resize(settings.value("mainx", "500").toInt(), settings.value("mainy", "320").toInt());
+
+    // start LAMMPS and initialize command completion
+    start_lammps();
+    QStringList command_list;
+    QFile internal_commands(":/lammps_internal_commands.txt");
+    if (internal_commands.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        while (!internal_commands.atEnd()) {
+            command_list << QString(internal_commands.readLine()).trimmed();
+        }
+    }
+    internal_commands.close();
+    int ncmds = lammps.style_count("command");
+    char buf[BUFLEN];
+    for (int i = 0; i < ncmds; ++i) {
+        if (lammps.style_name("command", i, buf, BUFLEN))
+            command_list << buf;
+    }
+    command_list.sort();
+    ui->textEdit->setCommandList(command_list);
 }
 
 LammpsGui::~LammpsGui()

tools/lammps-gui/lammpsgui.qrc

@@ -2,6 +2,9 @@
 <RCC>
   <qresource prefix="/">
     <file>lammps-icon-128x128.png</file>
+    <file>help_index.table</file>
+    <!-- This file is updated with: grep 'mycmd ==' ../../src/input.cpp | sed -e 's/^.*mycmd == "\(.*\)".*$/\1/' > lammps_internal_commands.txt -->
+    <file>lammps_internal_commands.txt</file>
     <file>antialias.png</file>
     <file>application-calc.png</file>
     <file>application-exit.png</file>
@@ -34,7 +37,6 @@
     <file>help-about.png</file>
     <file>help-browser.png</file>
     <file>help-faq.png</file>
-    <file>help_index.table</file>
     <file>image-x-generic.png</file>
     <file>media-playback-start-2.png</file>
     <file>media-playlist-repeat.png</file>

tools/lammps-gui/lammpswrapper.cpp

@@ -97,6 +97,33 @@ int LammpsWrapper::id_name(const char *keyword, int idx, char *buf, int len)
     return val;
 }
 
+int LammpsWrapper::style_count(const char *keyword)
+{
+    int val = 0;
+    if (lammps_handle) {
+#if defined(LAMMPS_GUI_USE_PLUGIN)
+        val = ((liblammpsplugin_t *)plugin_handle)->style_count(lammps_handle, keyword);
+#else
+        val = lammps_style_count(lammps_handle, keyword);
+#endif
+    }
+    return val;
+}
+
+int LammpsWrapper::style_name(const char *keyword, int idx, char *buf, int len)
+{
+    int val = 0;
+    if (lammps_handle) {
+#if defined(LAMMPS_GUI_USE_PLUGIN)
+        val =
+            ((liblammpsplugin_t *)plugin_handle)->style_name(lammps_handle, keyword, idx, buf, len);
+#else
+        val = lammps_style_name(lammps_handle, keyword, idx, buf, len);
+#endif
+    }
+    return val;
+}
+
 int LammpsWrapper::variable_info(int idx, char *buf, int len)
 {
     int val = 0;

tools/lammps-gui/lammpswrapper.h

@@ -35,6 +35,8 @@ public:
 
     int id_count(const char *idtype);
     int id_name(const char *idtype, int idx, char *buf, int buflen);
+    int style_count(const char *keyword);
+    int style_name(const char *keyword, int idx, char *buf, int buflen);
     int variable_info(int idx, char *buf, int buflen);
 
     double get_thermo(const char *keyword);