From 3e7d80bf308e6f07af40650cf8f1507e2e217370 Mon Sep 17 00:00:00 2001
From: krangelov <kr.angelov@gmail.com>
Date: Fri, 27 Aug 2021 14:44:42 +0200
Subject: [PATCH] reading & showing unicode identifiers

---
 src/runtime/c/pgf/expr.cxx         |  7 ++-
 src/runtime/c/pgf/expr.h           |  6 +++
 src/runtime/c/pgf/printer.cxx      | 68 +++++++++++++++++++++++++++---
 src/runtime/c/pgf/printer.h        |  2 +
 src/runtime/haskell/tests/basic.hs |  4 ++
 5 files changed, 80 insertions(+), 7 deletions(-)

diff --git a/src/runtime/c/pgf/expr.cxx b/src/runtime/c/pgf/expr.cxx
index 5a9057bdb..a54729f37 100644
--- a/src/runtime/c/pgf/expr.cxx
+++ b/src/runtime/c/pgf/expr.cxx
@@ -160,7 +160,7 @@ bool PgfExprParser::eof()
     return (token_tag == PGF_TOKEN_EOF);
 }
 
-static bool
+PGF_INTERNAL bool
 pgf_is_ident_first(uint32_t ucs)
 {
 	return (ucs == '_') ||
@@ -169,7 +169,7 @@ pgf_is_ident_first(uint32_t ucs)
            (ucs >= 192 && ucs <= 255 && ucs != 247 && ucs != 215);
 }
 
-static bool
+PGF_INTERNAL bool
 pgf_is_ident_rest(uint32_t ucs)
 {
 	return (ucs == '_') ||
@@ -211,6 +211,9 @@ void PgfExprParser::str_char()
         case '"':
             putc('\"');
             break;
+        case '\'':
+            putc('\'');
+            break;
         case 'n':
             putc('\n');
             break;
diff --git a/src/runtime/c/pgf/expr.h b/src/runtime/c/pgf/expr.h
index a80826e80..d75a83810 100644
--- a/src/runtime/c/pgf/expr.h
+++ b/src/runtime/c/pgf/expr.h
@@ -108,6 +108,12 @@ typedef struct PgfBind {
     PgfText var;
 } PgfBind;
 
+PGF_INTERNAL_DECL bool
+pgf_is_ident_first(uint32_t ucs);
+
+PGF_INTERNAL_DECL bool
+pgf_is_ident_rest(uint32_t ucs);
+
 class PGF_INTERNAL_DECL PgfExprParser {
     enum PGF_TOKEN_TAG {
         PGF_TOKEN_LPAR,
diff --git a/src/runtime/c/pgf/printer.cxx b/src/runtime/c/pgf/printer.cxx
index c6ae7f09b..4cb3b6738 100644
--- a/src/runtime/c/pgf/printer.cxx
+++ b/src/runtime/c/pgf/printer.cxx
@@ -209,14 +209,71 @@ PgfExpr PgfPrinter::efun(PgfText *name)
 {
     flush_lambdas();
 
-    puts(name);
+    bool normal_name = true;
+    
+    const uint8_t* start = (uint8_t*) name->text;
+    const uint8_t* end   = start + name->size;
+
+    const uint8_t* s = start;
+    while (s < end) {
+        uint32_t ucs = pgf_utf8_decode(&s);
+
+        if (!((s == (uint8_t*) start)
+                  ? pgf_is_ident_first(ucs)
+                  : pgf_is_ident_rest (ucs))) {
+            normal_name = false;
+            break;
+        }
+    }
+
+    if (normal_name) {
+        puts(name);
+    } else {
+        PgfText *charbuf = (PgfText *) alloca(sizeof(PgfText)+7);
+
+        puts("'");
+        while (start < end) {
+            const uint8_t* s = start;
+            uint32_t ucs = pgf_utf8_decode(&s);
+
+            switch (ucs) {
+            case '\\':
+                puts("\\\\");
+                break;
+            case '\'':
+                puts("\\'");
+                break;
+            case '\n':
+                puts("\\n");
+                break;
+            case '\r':
+                puts("\\r");
+                break;
+            case '\b':
+                puts("\\b");
+                break;
+            case '\t':
+                puts("\\t");
+                break;
+            case '\0':
+                puts("\\0");
+                break;
+            default:
+                charbuf->size = s-start;
+                memcpy(charbuf->text, start, charbuf->size);
+                charbuf->text[charbuf->size] = 0;
+                puts(charbuf);
+            }
+            start = s;
+        }
+        puts("'");
+    }
+
     return 0;
 }
 
 PgfExpr PgfPrinter::evar(int index)
 {
-    flush_lambdas();
-
     PgfPrintContext *var = ctxt;
     for (int i = 0; i < index; i++) {
         if (var == NULL)
@@ -224,9 +281,10 @@ PgfExpr PgfPrinter::evar(int index)
         var = var->next;
     }
     if (var == NULL) {
+        flush_lambdas();
         nprintf(4, "#%d", index);
     } else {
-        puts(&var->name);
+        efun(&var->name);
     }
     return 0;
 }
@@ -353,7 +411,7 @@ PgfType PgfPrinter::dtyp(int n_hypos, PgfTypeHypo *hypos,
         puts(" -> ");
     }
 
-    puts(cat);
+    efun(cat);
 
     for (int i = 0; i < n_exprs; i++) {
         puts(" ");
diff --git a/src/runtime/c/pgf/printer.h b/src/runtime/c/pgf/printer.h
index 378c27492..7a7e67987 100644
--- a/src/runtime/c/pgf/printer.h
+++ b/src/runtime/c/pgf/printer.h
@@ -46,6 +46,8 @@ public:
     // it will be allocated automatically.
     void nprintf(size_t buf_size, const char *format, ...) __attribute__ ((format (printf, 3, 4)));
 
+    void print_name(PgfText *name);
+
     PgfText *get_text();
 
     virtual PgfExpr eabs(PgfBindType btype, PgfText *name, PgfExpr body);
diff --git a/src/runtime/haskell/tests/basic.hs b/src/runtime/haskell/tests/basic.hs
index ce8d6ad17..83e02c0f5 100644
--- a/src/runtime/haskell/tests/basic.hs
+++ b/src/runtime/haskell/tests/basic.hs
@@ -67,6 +67,10 @@ main = do
              ,TestCase (assertEqual "fresh variables 3" "\\v,v1,v2->v1" (showExpr [] (EAbs Explicit "v" (EAbs Explicit "v" (EAbs Explicit "v" (EVar 1))))))
              ,TestCase (assertBool "large integer 1" (null [n | n <- ns, showExpr [] (ELit (LInt n)) /= show n]))
              ,TestCase (assertBool "large integer 2" (null [n | n <- ns, readExpr (show n) /= Just (ELit (LInt n))]))
+             ,TestCase (assertEqual "unicode names 1" (Just "'абв'") (fmap (showExpr []) (readExpr "'абв'")))
+             ,TestCase (assertEqual "unicode names 2" (Just "ab") (fmap (showExpr []) (readExpr "'ab'")))
+             ,TestCase (assertEqual "unicode names 3" (Just "a'b") (fmap (showExpr []) (readExpr "'a\\'b'")))
+             ,TestCase (assertEqual "unicode names 4" (Just "'а\\'б'") (fmap (showExpr []) (readExpr "'а\\'б'")))
              ]
 
 testLoadFailure fpath = do