pp support for regex expressions is more-or-less standard syntax

src/ast/seq_decl_plugin.cpp

@@ -1465,3 +1465,191 @@ bool seq_util::re::is_epsilon(expr* r) const {
 app* seq_util::re::mk_epsilon(sort* seq_sort) {
     return mk_to_re(u.str.mk_empty(seq_sort));
 }
+
+/*
+  Provides a standard pretty printed view of the regex r when possible.
+*/
+std::string seq_util::re::pp(expr* r) {
+    SASSERT(u.is_re(r));
+    std::ostringstream buffer;
+    pp_compact_to_buffer(buffer, r);
+    return buffer.str();
+}
+
+void seq_util::re::pp_compact_to_buffer(std::ostringstream& buffer, expr* r) {
+    SASSERT(u.is_re(r));
+    expr* r1 = nullptr, * r2 = nullptr, * s = nullptr, * s2 = nullptr;
+    unsigned lo = 0, hi = 0;
+    if (is_full_char(r))
+        buffer << ".";
+    else if (is_full_seq(r))
+        buffer << ".*";
+    else if (is_to_re(r, s))
+        pp_compact_helper_seq(buffer, s);
+    else if (is_range(r, s, s2))
+        pp_compact_helper_range(buffer, s, s2);
+    else if (is_epsilon(r))
+        buffer << "()";
+    else if (is_empty(r))
+        buffer << "[]";
+    else if (is_concat(r, r1, r2)) {
+        pp_compact_to_buffer(buffer, r1);
+        pp_compact_to_buffer(buffer, r2);
+    }
+    else if (is_union(r, r1, r2)) {
+        pp_compact_to_buffer(buffer, r1);
+        buffer << "|";
+        pp_compact_to_buffer(buffer, r2);
+    }
+    else if (is_intersection(r, r1, r2)) {
+        buffer << "(";
+        pp_compact_to_buffer(buffer, r1);
+        buffer << ")&(";
+        pp_compact_to_buffer(buffer, r2);
+        buffer << ")";
+    }
+    else if (is_complement(r, r1)) {
+        buffer << "~";
+        if (pp_can_skip_parenth(r1))
+            pp_compact_to_buffer(buffer, r1);
+        else {
+            buffer << "(";
+            pp_compact_to_buffer(buffer, r1);
+            buffer << ")";
+        }
+    }
+    else if (is_plus(r, r1))
+        if (pp_can_skip_parenth(r1)) {
+            pp_compact_to_buffer(buffer, r1);
+            buffer << "+";
+        }
+        else {
+            buffer << "(";
+            pp_compact_to_buffer(buffer, r1);
+            buffer << ")+";
+        }
+    else if (is_star(r, r1))
+        if (pp_can_skip_parenth(r1)) {
+            pp_compact_to_buffer(buffer, r1);
+            buffer << "*";
+        }
+        else {
+            buffer << "(";
+            pp_compact_to_buffer(buffer, r1);
+            buffer << ")*";
+        }
+    else if (is_loop(r, r1, lo))
+        if (pp_can_skip_parenth(r1))
+        {
+            pp_compact_to_buffer(buffer, r1);
+            buffer << "{" << std::to_string(lo) << ",}";
+        }
+        else {
+            buffer << "(";
+            pp_compact_to_buffer(buffer, r1);
+            buffer << "){" << std::to_string(lo) << ",}";
+        }
+    else if (is_loop(r, r1, lo, hi))
+        if (pp_can_skip_parenth(r1))
+        {
+            pp_compact_to_buffer(buffer, r1);
+            buffer << "{" << std::to_string(lo) << "," << std::to_string(hi) << "}";
+        }
+        else {
+            buffer << "(";
+            pp_compact_to_buffer(buffer, r1);
+            buffer << "){" << std::to_string(lo) << "," << std::to_string(hi) << "}";
+        }
+    else if (is_diff(r, r1, r2)) {
+        buffer << "(";
+        pp_compact_to_buffer(buffer, r1);
+        buffer << ")\\(";
+        pp_compact_to_buffer(buffer, r2);
+        buffer << ")";
+    }
+    else if (m.is_ite(r, s, r1, r2)) {
+        buffer << "if(" << mk_pp(s, m) << ",";
+        pp_compact_to_buffer(buffer, r1);
+        buffer << ",";
+        pp_compact_to_buffer(buffer, r2);
+        buffer << ")";
+    }
+    else if (is_opt(r, r1))
+        if (pp_can_skip_parenth(r1)) {
+            pp_compact_to_buffer(buffer, r1);
+            buffer << "?";
+        }
+        else {
+            buffer << "(";
+            pp_compact_to_buffer(buffer, r1);
+            buffer << ")?";
+        }
+    else if (is_reverse(r, r1)) {
+        buffer << "reverse(";
+        pp_compact_to_buffer(buffer, r1);
+        buffer << ")";
+    }
+    else
+        // Else: derivative or is_of_pred
+        buffer << mk_pp(r, m);
+}
+
+void seq_util::re::pp_compact_helper_seq(std::ostringstream& buffer, expr* s) {
+    SASSERT(u.is_seq(s));
+    if (m.is_value(s)) {
+        SASSERT(s->get_kind() == ast_kind::AST_APP);
+        if (u.str.is_concat(s)) {
+            expr_ref_vector es(m);
+            u.str.get_concat(s, es);
+            for (unsigned i = 0; i < es.size(); i++)
+                if (u.str.is_unit(es.get(i)))
+                    pp_seq_unit(buffer, es.get(i));
+                else
+                    buffer << mk_pp(es.get(i), m);
+        }
+        else
+            pp_seq_unit(buffer, s);
+    }
+    else
+        buffer << mk_pp(s, m);
+}
+
+void seq_util::re::pp_compact_helper_range(std::ostringstream& buffer, expr* s1, expr* s2) {
+    buffer << "[";
+    if (u.str.is_unit(s1))
+        pp_seq_unit(buffer, s1);
+    else 
+        buffer << mk_pp(s1, m);
+    buffer << "-";
+    if (u.str.is_unit(s2))
+        pp_seq_unit(buffer, s2);
+    else
+        buffer << mk_pp(s1, m);
+    buffer << "]";
+}
+
+bool seq_util::re::pp_can_skip_parenth(expr* r) {
+    expr* s;
+    return ((is_to_re(r, s) && u.str.is_unit(s)) || is_range(r));
+}
+
+void seq_util::re::pp_seq_unit(std::ostringstream& buffer, expr* s) {
+    expr* e;
+    if (u.str.is_unit(s, e)) {
+        rational r;
+        unsigned sz;
+        if (u.bv().is_numeral(e, r, sz) && sz == 8 && r.is_unsigned()) {
+            unsigned n = r.get_unsigned();
+            if (32 < n && n < 127)
+                buffer << (char)n;
+            else if (n < 10)
+                buffer << "\\x0" << std::hex << n;
+            else
+                buffer << "\\x" << std::hex << n;
+        }
+        else
+            buffer << mk_pp(s, m);
+    }
+    else
+        buffer << mk_pp(s, m);
+}