#include <config.h>
#include "MathClass.h"
+#include "MathSupport.h"
+#include "MetricsInfo.h"
+#include "FontInfo.h"
+
+#include "support/debug.h"
#include "support/docstring.h"
#include "support/lassert.h"
+#include <ostream>
+
using namespace std;
namespace lyx {
}
+/*
+ * The TeXbook presents in Appendix G a set of 22 rules (!) explaining
+ * how to typeset mathematic formulas. Of interest here are rules 5
+ * and 6:
+
+ * 5. If the current item is a Bin atom, and if this was the first
+ * atom in the list, or if the most recent previous atom was Bin,
+ * Op, Rel, Open, or Punct, change the current Bin to Ord [and
+ * continue with Rule 14. Otherwise continue with Rule 17]
+ *
+ * 6. If the current item is a Rel or Close or Punct atom, and if the
+ * most recent previous atom was Bin, change that previous Bin to
+ * Ord. [Continue with Rule 17.]
+ */
+void update_class(MathClass & mc, MathClass const prev, MathClass const next)
+{
+ if (mc == MC_BIN
+ && (prev == MC_BIN || prev == MC_OP || prev == MC_OPEN
+ || prev == MC_PUNCT || prev == MC_REL
+ || next == MC_CLOSE || next == MC_PUNCT || next == MC_REL))
+ mc = MC_ORD;
+}
+
+
+/*
+ * This table of spacing between two classes can be found p. 170 of
+ * The TeXbook.
+ *
+ * The line is the class of the first class, and the column the second
+ * class. The number encodes the spacing between the two atoms, as
+ * follows
+ *
+ * + 0: no spacing
+ * + 1: thin mu skip
+ * + 2: med mu skip
+ * + 3: thick mu skip
+ * + 9: should never happen
+ * + negative value: either 0 if the atom is in script or scriptscript mode,
+ * or the spacing given by the absolute value.
+ */
+int pair_spc[MC_UNKNOWN][MC_UNKNOWN] = {
+// ORD OP BIN REL OPEN CLOSE PUNCT INNER
+ { 0, 1, -2, -3, 0, 0, 0, -1}, // ORD
+ { 1, 1, 9, -3, 0, 0, 0, -1}, // OP
+ { -2, -2, 9, 9, -2, 9, 9, -2}, // BIN
+ { -3, -3, 9, 0, -3, 0, 0, -3}, // REL
+ { 0, 0, 9, 0, 0, 0, 0, 0}, // OPEN
+ { 0, 1, -2, -3, 0, 0, 0, -1}, // CLOSE
+ { -1, -1, 9, -1, -1, -1, -1, -1}, // PUNCT
+ { -1, 1, -2, -3, -1, 0, -1, -1}, // INNER
+};
+
+
+int class_spacing(MathClass const mc1, MathClass const mc2,
+ MetricsBase const & mb)
+{
+ int spc_code = pair_spc[mc1][mc2];
+ //lyxerr << class_to_string(mc1) << "+" << class_to_string(mc2)
+ // << "=" << spc_code << " @" << mb.style << endl;
+ if (spc_code < 0) {
+ switch (mb.style) {
+ case LM_ST_DISPLAY:
+ case LM_ST_TEXT:
+ spc_code = abs(spc_code);
+ break;
+ case LM_ST_SCRIPT:
+ case LM_ST_SCRIPTSCRIPT:
+ spc_code = 0;
+ }
+ }
+
+ int spc = 0;
+ switch(spc_code) {
+ case 0:
+ break;
+ case 1:
+ spc = mathed_thinmuskip(mb.font);
+ break;
+ case 2:
+ spc = mathed_medmuskip(mb.font);
+ break;
+ case 3:
+ spc = mathed_thickmuskip(mb.font);
+ break;
+ default:
+ LYXERR0("Impossible pair of classes: (" << mc1 << ", " << mc2 << ")");
+ LATTEST(false);
+ }
+ return spc;
+}
+
} // namespace lyx