Refactor PrismCL switch definitions and -help text generation

prism/src/prism/ArgConsumer.java

@@ -0,0 +1,151 @@
+//==============================================================================
+//
+//	Copyright (c) 2026-
+//	Authors:
+//	* Dave Parker <david.parker@cs.ox.ac.uk> (University of Oxford)
+//
+//------------------------------------------------------------------------------
+//
+//	This file is part of PRISM.
+//
+//	PRISM is free software; you can redistribute it and/or modify
+//	it under the terms of the GNU General Public License as published by
+//	the Free Software Foundation; either version 2 of the License, or
+//	(at your option) any later version.
+//
+//	PRISM is distributed in the hope that it will be useful,
+//	but WITHOUT ANY WARRANTY; without even the implied warranty of
+//	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//	GNU General Public License for more details.
+//
+//	You should have received a copy of the GNU General Public License
+//	along with PRISM; if not, write to the Free Software Foundation,
+//	Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//
+//==============================================================================
+
+package prism;
+
+/**
+ * Wraps a CLI argument array and current position for cleaner switch handling.
+ * Provides typed argument consumption that throws {@link PrismException}s on error.
+ */
+class ArgConsumer
+{
+	private final String[] args;
+	private int i;
+	private String optionsString;
+
+	/**
+	 * Creates a consumer over the full argument array, positioned before the first element.
+	 * The caller drives iteration by calling {@link #advance()} then {@link #parseSwitch(String)}.
+	 */
+	ArgConsumer(String[] args)
+	{
+		this.args = args;
+		this.i = -1;
+		this.optionsString = null;
+	}
+
+	/**
+	 * Advances to and returns the next raw argument.
+	 * The caller must check {@link #hasNext()} before calling this.
+	 */
+	String advance()
+	{
+		return args[++i];
+	}
+
+	/**
+	 * Parses a raw CLI token as a switch: strips the leading {@code -} or {@code --},
+	 * splits on the first {@code :} to extract any sub-options, stores them in
+	 * {@link #optionsString()}, and returns the switch name.
+	 * Returns {@code null} if the token does not start with {@code -} (i.e. it is a filename).
+	 * Throws if the switch name would be empty (bare {@code -} or {@code --}).
+	 */
+	String parseSwitch(String arg) throws PrismException
+	{
+		if (arg.isEmpty() || arg.charAt(0) != '-') {
+			optionsString = null;
+			return null;
+		}
+		String sw = arg.substring(1);
+		if (sw.isEmpty()) throw new PrismException("Invalid empty switch");
+		if (sw.charAt(0) == '-') {
+			sw = sw.substring(1);
+			if (sw.isEmpty()) throw new PrismException("Invalid empty switch");
+		}
+		int colon = sw.indexOf(':');
+		if (colon == -1) {
+			optionsString = null;
+			return sw;
+		}
+		optionsString = sw.substring(colon + 1);
+		return sw.substring(0, colon);
+	}
+
+	/** Colon sub-options from {@code -switch:opts} syntax (e.g. {@code "upper,lower"} from {@code -intervaliter:upper,lower}), or {@code null}. */
+	String optionsString()
+	{
+		return optionsString;
+	}
+
+	/** Returns the current index (updated by any {@code next*()} calls). */
+	int index()
+	{
+		return i;
+	}
+
+	/** Whether a next argument is available. */
+	boolean hasNext()
+	{
+		return i < args.length - 1;
+	}
+
+	/** Returns the next argument without consuming it, or {@code null} if there is none. */
+	String peek()
+	{
+		return hasNext() ? args[i + 1] : null;
+	}
+
+	/** Consume and return the next argument, or throw a descriptive error for switch {@code sw}. */
+	String next(String sw) throws PrismException
+	{
+		if (!hasNext())
+			throw new PrismException("No value specified for -" + sw + " switch");
+		return args[++i];
+	}
+
+	/** Consume the next argument, parse it as an {@code int}, and return it. */
+	int nextInt(String sw) throws PrismException
+	{
+		String s = next(sw);
+		try {
+			return Integer.parseInt(s);
+		} catch (NumberFormatException e) {
+			throw new PrismException("Invalid value \"" + s + "\" for -" + sw + " switch");
+		}
+	}
+
+	/** Consume the next argument, parse it as a {@code double}, and return it. */
+	double nextDouble(String sw) throws PrismException
+	{
+		String s = next(sw);
+		try {
+			return Double.parseDouble(s);
+		} catch (NumberFormatException e) {
+			throw new PrismException("Invalid value \"" + s + "\" for -" + sw + " switch");
+		}
+	}
+
+	/** Consume the next argument, parse it as a {@code long}, and return it. */
+	long nextLong(String sw) throws PrismException
+	{
+		String s = next(sw);
+		try {
+			return Long.parseLong(s);
+		} catch (NumberFormatException e) {
+			throw new PrismException("Invalid value \"" + s + "\" for -" + sw + " switch");
+		}
+	}
+}