test: runtime parity tests

tests/lit/single/literals/integer_hex_binary.st

@@ -0,0 +1,43 @@
+// RUN: (%COMPILE %s && %RUN) | %CHECK %s
+
+// NOTE: The runtime monitoring write API depends on these exact values.
+// If this test fails, check whether the runtime parser needs a matching update.
+
+FUNCTION main : DINT
+VAR
+    // Two's complement INT hex literals
+    i_ffff      : INT  := 16#FFFF;
+    i_8000      : INT  := 16#8000;
+    i_7fff      : INT  := 16#7FFF;
+    i_neg_ffff  : INT  := -16#FFFF;
+    i_neg_000f  : INT  := -16#000F;
+
+    // Two's complement DINT hex literals
+    d_ffffffff  : DINT := 16#FFFFFFFF;
+    d_80000000  : DINT := 16#80000000;
+
+    // Two's complement INT binary literal
+    i_bin_ffff  : INT  := 2#1111111111111111;
+END_VAR
+    // --- INT hex ---
+    // CHECK: 16#FFFF as INT: -1
+    printf('16#FFFF as INT: %d$N', i_ffff);
+    // CHECK: 16#8000 as INT: -32768
+    printf('16#8000 as INT: %d$N', i_8000);
+    // CHECK: 16#7FFF as INT: 32767
+    printf('16#7FFF as INT: %d$N', i_7fff);
+    // CHECK: -16#FFFF as INT: 1
+    printf('-16#FFFF as INT: %d$N', i_neg_ffff);
+    // CHECK: -16#000F as INT: -15
+    printf('-16#000F as INT: %d$N', i_neg_000f);
+
+    // --- DINT hex ---
+    // CHECK: 16#FFFFFFFF as DINT: -1
+    printf('16#FFFFFFFF as DINT: %d$N', d_ffffffff);
+    // CHECK: 16#80000000 as DINT: -2147483648
+    printf('16#80000000 as DINT: %d$N', d_80000000);
+
+    // --- INT binary ---
+    // CHECK: 2#1111111111111111 as INT: -1
+    printf('2#1111111111111111 as INT: %d$N', i_bin_ffff);
+END_FUNCTION

tests/lit/single/string_escapes/string_escapes.st

@@ -0,0 +1,51 @@
+// RUN: (%COMPILE %s && %RUN) | %CHECK %s
+
+// NOTE: The runtime monitoring write API depends on these exact values.
+// If this test fails, check whether the runtime parser needs a matching update.
+
+FUNCTION main : DINT
+VAR
+    // 1. Valid hex escapes (ASCII range)
+    s_hex_hi        : STRING[10] := '$48$49';
+
+    // 2. Invalid UTF-8 hex escapes (lossy replacement)
+    s_invalid_80    : STRING[10] := '$80';
+    s_caf_e9        : STRING[10] := 'caf$E9';
+    s_invalid_ff    : STRING[10] := '$FF';
+    s_valid_utf8    : STRING[10] := '$F0$9F$92$96';
+
+    // 3. Named escapes
+    s_dollar        : STRING[20] := 'Price: $$100';
+    s_newline       : STRING[30] := 'Line1$NLine2';
+    s_tab           : STRING[20] := 'Col1$TCol2';
+    s_cr            : STRING[20] := 'Before$RAfter';
+    s_quote         : STRING[20] := '$'quoted$'';
+END_VAR
+    // --- Valid hex escapes ---
+    // CHECK: HI
+    printf('%s$N', REF(s_hex_hi));
+
+    // --- Invalid UTF-8 (lossy → U+FFFD replacement character) ---
+    // CHECK: �
+    printf('%s$N', REF(s_invalid_80));
+    // CHECK: caf�
+    printf('%s$N', REF(s_caf_e9));
+    // CHECK: �
+    printf('%s$N', REF(s_invalid_ff));
+    // CHECK: 💖
+    printf('%s$N', REF(s_valid_utf8));
+
+    // --- Named escapes ---
+    // Known bug: '$$' followed by 2 hex digits is double-processed in the
+    // committed parser (two-pass). '$$10' → '$10' (pass 1) → 0x10 DLE (pass 2).
+    // Remove XCHECK and restore CHECK once the single-pass fix lands.
+    // XCHECK: Price: $100
+    printf('%s$N', REF(s_dollar));
+    // CHECK: Line1
+    // CHECK: Line2
+    printf('%s$N', REF(s_newline));
+    // CHECK: Col1	Col2
+    printf('%s$N', REF(s_tab));
+    // CHECK: 'quoted'
+    printf('%s$N', REF(s_quote));
+END_FUNCTION

tests/lit/single/string_escapes/string_incomplete_hex.st

@@ -0,0 +1,13 @@
+// RUN: not %COMPILE %s
+// XFAIL: *
+// STRING hex escapes require exactly 2 hex digits ($hh). '$A' provides only
+// one hex digit before end-of-string, which is an incomplete escape sequence
+// and should be a compile error per IEC 61131-3.
+// Currently the compiler silently keeps '$' and 'A' as literal characters.
+
+FUNCTION main : DINT
+VAR
+    s : STRING[10] := '$A';
+END_VAR
+    main := 0;
+END_FUNCTION

tests/lit/single/string_escapes/string_invalid_escape.st

@@ -0,0 +1,12 @@
+// RUN: not %COMPILE %s
+// XFAIL: *
+// '$Q' is not a valid named escape (not $N/$R/$T/$L/$P/$$/$$') and 'Q' is not
+// a hex digit, so this should be a compile error per IEC 61131-3.
+// Currently the compiler silently keeps '$Q' as the two literal characters.
+
+FUNCTION main : DINT
+VAR
+    s : STRING[20] := 'test$Qtest';
+END_VAR
+    main := 0;
+END_FUNCTION

tests/lit/single/string_escapes/string_trailing_dollar.st

@@ -0,0 +1,12 @@
+// RUN: not %COMPILE %s
+// XFAIL: *
+// A trailing '$' with nothing following it is an invalid escape sequence
+// and should be a compile error per IEC 61131-3.
+// Currently the compiler silently keeps the '$' as a literal character.
+
+FUNCTION main : DINT
+VAR
+    s : STRING[10] := 'hello$';
+END_VAR
+    main := 0;
+END_FUNCTION

tests/lit/single/string_escapes/wstring_escapes.st

@@ -0,0 +1,47 @@
+// RUN: (%COMPILE %s && %RUN) | %CHECK %s
+
+// NOTE: The runtime monitoring write API depends on these exact values.
+// If this test fails, check whether the runtime parser needs a matching update.
+
+FUNCTION main : DINT
+VAR
+    // 4. WSTRING — valid hex escapes
+    w_hex_hi        : WSTRING[10] := "$0048$0049";
+    w_surrogate     : WSTRING[10] := "$D83D$DE00";
+
+    // 5. WSTRING — unpaired surrogate replacement
+    w_high_only     : WSTRING[10] := "$D800";
+    w_low_only      : WSTRING[10] := "$DE00";
+    w_high_not_low  : WSTRING[10] := "$D83D$0041";
+    w_reversed      : WSTRING[10] := "$DE00$D83D";
+
+    // 6. WSTRING — named escapes
+    w_dollar        : WSTRING[20] := "Price: $$100";
+    w_newline       : WSTRING[30] := "Line1$NLine2";
+    w_dquote        : WSTRING[20] := "$"quoted$"";
+END_VAR
+    // --- Valid hex escapes ---
+    // CHECK: HI
+    printf('%s$N', REF(TO_STRING(w_hex_hi)));
+    // CHECK: 😀
+    printf('%s$N', REF(TO_STRING(w_surrogate)));
+
+    // --- Unpaired surrogates (lossy → U+FFFD) ---
+    // CHECK: �
+    printf('%s$N', REF(TO_STRING(w_high_only)));
+    // CHECK: �
+    printf('%s$N', REF(TO_STRING(w_low_only)));
+    // CHECK: �A
+    printf('%s$N', REF(TO_STRING(w_high_not_low)));
+    // CHECK: ��
+    printf('%s$N', REF(TO_STRING(w_reversed)));
+
+    // --- Named escapes ---
+    // CHECK: Price: $100
+    printf('%s$N', REF(TO_STRING(w_dollar)));
+    // CHECK: Line1
+    // CHECK: Line2
+    printf('%s$N', REF(TO_STRING(w_newline)));
+    // CHECK: "quoted"
+    printf('%s$N', REF(TO_STRING(w_dquote)));
+END_FUNCTION

tests/lit/single/string_escapes/wstring_incomplete_hex.st

@@ -0,0 +1,13 @@
+// RUN: not %COMPILE %s
+// XFAIL: *
+// WSTRING hex escapes require exactly 4 hex digits ($hhhh). '$004' provides
+// only three hex digits before end-of-string, which is an incomplete escape
+// sequence and should be a compile error per IEC 61131-3.
+// Currently the compiler silently keeps '$' and the remaining chars as literals.
+
+FUNCTION main : DINT
+VAR
+    s : WSTRING[10] := "$004";
+END_VAR
+    main := 0;
+END_FUNCTION

tests/lit/single/string_escapes/wstring_invalid_escape.st

@@ -0,0 +1,12 @@
+// RUN: not %COMPILE %s
+// XFAIL: *
+// '$Q' is not a valid named escape and 'Q' is not a hex digit, so this should
+// be a compile error per IEC 61131-3.
+// Currently the compiler silently keeps '$Q' as the two literal characters.
+
+FUNCTION main : DINT
+VAR
+    s : WSTRING[20] := "test$Qtest";
+END_VAR
+    main := 0;
+END_FUNCTION

tests/lit/single/string_escapes/wstring_trailing_dollar.st

@@ -0,0 +1,12 @@
+// RUN: not %COMPILE %s
+// XFAIL: *
+// A trailing '$' with nothing following it is an invalid escape sequence
+// and should be a compile error per IEC 61131-3.
+// Currently the compiler silently keeps the '$' as a literal character.
+
+FUNCTION main : DINT
+VAR
+    s : WSTRING[10] := "hello$";
+END_VAR
+    main := 0;
+END_FUNCTION