Merge branch 'topic/1454' into 'master'

Fix interpolated string support

Closes #1454

See merge request eng/libadalang/libadalang!1786

ada/nodes.lkt

@@ -12080,13 +12080,22 @@ class DeclExpr: Expr {
 class FormatStringLiteral: Expr {
     @parse_field opening_chunk: FormatStringTokStart
     @parse_field mid_exprs: ASTList[FormatStringChunk]
-    @parse_field trailing_expr: FormatStringChunk
+
+    # This field is null when no expressions to expand are given in the
+    # interpolated string, for example with `f"a dummy interpolated string"`.
+    @parse_field @nullable trailing_expr: FormatStringChunk
 
     @with_dynvars(env, origin, entry_point)
     fun xref_equation(): Equation = (
-        (
-            %predicate(BaseTypeDecl.allows_string_literal, node.expected_type_var(), error_location=node) and %eq(node.expected_type_var(), node.type_var())
-        ) and self.trailing_expr.sub_equation()
+         %predicate(
+             BaseTypeDecl.allows_string_literal,
+             node.expected_type_var(),
+             error_location=node
+         ) and %eq(node.expected_type_var(), node.type_var())
+         and self.trailing_expr.do(
+            (te) => te.sub_equation(),
+            default_val=%true
+         )
     ) and self.mid_exprs.logic_all((m) => m.expr.sub_equation())
 }
 
@@ -15801,6 +15810,11 @@ class FormatStringTokMid: FormatStringTokNode implements TokenNode {
 class FormatStringTokStart: FormatStringTokNode implements TokenNode {
 }
 
+|" Node holding a formatting "string" token. This token is used when the
+|" corresponding interpolated string doesn't have any expression to expand.
+class FormatStringTokString: FormatStringTokStart implements TokenNode {
+}
+
 |" List of statements, with optional exception handlers (:rmlink:`11.2`).
 @snaps
 class HandledStmts: AdaNode {

ada/parser.lkt

@@ -898,11 +898,19 @@ grammar ada_grammar {
     identifier <- Identifier(@Identifier)
     char_literal <- CharLiteral(@Char)
     string_literal <- StringLiteral(@String)
-    format_string_literal <- FormatStringLiteral(
-        FormatStringTokStart(@FormatStringStart)
-        list*(FormatStringChunk(expr
-        FormatStringTokMid(@FormatStringMid)))
-        FormatStringChunk(expr FormatStringTokEnd(@FormatStringEnd))
+    format_string_literal <- or(
+        # String interpolation with interpolated expressions
+        FormatStringLiteral(
+            FormatStringTokStart(@FormatStringStart)
+            list*(FormatStringChunk(expr FormatStringTokMid(@FormatStringMid)))
+            FormatStringChunk(expr FormatStringTokEnd(@FormatStringEnd))
+        )
+
+        # String interpolation without interpolated expressions
+        | FormatStringLiteral(
+            FormatStringTokString(@FormatStringString)
+            null(ASTList[FormatStringChunk]) null(FormatStringChunk)
+        )
     )
     defining_id <- DefiningName(identifier)
     dec_literal <- RealLiteral(@Decimal)

ada/tokens.lkt

@@ -4,6 +4,10 @@ lexer ada_lexer {
     val p_format_string_start = p"f\\\"(\\\"\\\"|{bracket_char}|[^\\n\\\"\\{])*\\{"
     val p_format_string_mid = p"\\}(\\\"\\\"|{bracket_char}|[^\\n\\\"\\{])*\\{"
     val p_format_string_end = p"\\}(\\\"\\\"|{bracket_char}|[^\\n\\\"\\{])*\\\""
+
+    # Simple format string literal without expressions to expand
+    val p_format_string_string = p"f\\\"(\\\"\\\"|{bracket_char}|[^\\n\\\"\\{])*\\\""
+
     val p_percent_string = p"%(%%|{bracket_char}|[^\\n%])*%"
     val digit = p"[0-9]"
     val extended_digit = p"[0-9a-zA-Z]"
@@ -161,6 +165,7 @@ lexer ada_lexer {
     }
 
     String <- or(p"{p_string}" | p"{p_percent_string}")
+    FormatStringString <- p"{p_format_string_string}"
     FormatStringStart <- p"{p_format_string_start}"
     FormatStringMid <- p"{p_format_string_mid}"
     FormatStringEnd <- p"{p_format_string_end}"

contrib/highlight/highlighter.adb

@@ -27,6 +27,7 @@ package body Highlighter is
          Ada_Format_String_End
            | Ada_Format_String_Mid
            | Ada_Format_String_Start
+           | Ada_Format_String_String
            | Ada_String
          => String_Literal,
 

testsuite/tests/parser/interpolated_string_0/input

@@ -0,0 +1 @@
+f"a{A}B{B}C{C}D{D}"

testsuite/tests/parser/interpolated_string_0/test.out

@@ -0,0 +1,26 @@
+FormatStringLiteral[1:1-1:20]
+|f_opening_chunk:
+|  FormatStringTokStart[1:1-1:5]: f"a{
+|f_mid_exprs:
+|  FormatStringChunkList[1:5-1:17]
+|  |  FormatStringChunk[1:5-1:9]
+|  |  |f_expr:
+|  |  |  Id[1:5-1:6]: A
+|  |  |f_string_tok:
+|  |  |  FormatStringTokMid[1:6-1:9]: }B{
+|  |  FormatStringChunk[1:9-1:13]
+|  |  |f_expr:
+|  |  |  Id[1:9-1:10]: B
+|  |  |f_string_tok:
+|  |  |  FormatStringTokMid[1:10-1:13]: }C{
+|  |  FormatStringChunk[1:13-1:17]
+|  |  |f_expr:
+|  |  |  Id[1:13-1:14]: C
+|  |  |f_string_tok:
+|  |  |  FormatStringTokMid[1:14-1:17]: }D{
+|f_trailing_expr:
+|  FormatStringChunk[1:17-1:20]
+|  |f_expr:
+|  |  Id[1:17-1:18]: D
+|  |f_string_tok:
+|  |  FormatStringTokEnd[1:18-1:20]: }"

testsuite/tests/parser/interpolated_string_0/test.yaml

@@ -0,0 +1,2 @@
+driver: parser
+rule: format_string_literal

testsuite/tests/parser/interpolated_string_1/input

@@ -0,0 +1 @@
+f"lol"

testsuite/tests/parser/interpolated_string_1/test.out

@@ -0,0 +1,6 @@
+FormatStringLiteral[1:1-1:7]
+|f_opening_chunk:
+|  FormatStringTokString[1:1-1:7]: f"lol"
+|f_mid_exprs:
+|  FormatStringChunkList[1:7-1:7]: <empty list>
+|f_trailing_expr: <null>

testsuite/tests/parser/interpolated_string_1/test.yaml

@@ -0,0 +1,2 @@
+driver: parser
+rule: format_string_literal