From 972a442e17c300e869fae94853de16471f58f633 Mon Sep 17 00:00:00 2001
From: Miguel Ceriani <miguel.ceriani@gmail.com>
Date: Tue, 15 Apr 2025 12:44:27 +0200
Subject: [PATCH 1/3] Add function to generate back textual syntax from AST

---
 jqjq.jq | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)

diff --git a/jqjq.jq b/jqjq.jq
index bd92502..caf6a14 100644
--- a/jqjq.jq
+++ b/jqjq.jq
@@ -2090,6 +2090,123 @@ def eval_ast($query; $path; $env; undefined_func):
 def eval_ast($ast):
   eval_ast($ast; []; {}; undefined_func_error);
 
+def ast_tostring:
+  def _pattern:
+    if .name then .name
+    elif .array then "[\([.array[] | _pattern] | join(", "))]"
+    elif .object then "{\([.object[] | "\(.key)\(if .val then ": \(.val | _pattern)" else "" end)"] | join(", "))}"
+    else error("unsupported type of pattern: \(.)")
+    end;
+  def _f:
+    def _index:
+      ".\(
+        if .start then
+          "[\(.start | _f)\(if .end then ":\(.end | _f)" else "" end)]"
+        elif .name then .name
+        elif .str then .str.str | tojson
+        else error("unsupported type of index: \(.)")
+        end
+      )";
+    . as {term: {type: $type}, $op, $func_defs}
+    | if $type then .term |
+        "\(
+          if $func_defs then [
+            $func_defs.[]
+            | "def \(.name)\(
+              if .args then "(\(.args | join(", ")))"
+              else ""
+              end
+            ): \(.body | _f); "
+          ] | join("")
+          else ""
+          end
+        )\(
+          if $type == "TermTypeNull" then "null"
+          elif $type == "TermTypeNumber" then .number | tostring
+          elif $type == "TermTypeString" then
+            if .str then
+              .str | tojson
+            else 
+              [
+                .queries.[] | _f |
+                if .[0:1] == "\""
+                  then .[1:-1]
+                  else "\\\(.)"
+                end
+              ] | join("") | "\"\(.)\""
+            end
+          elif $type == "TermTypeTrue" then "true"
+          elif $type == "TermTypeFalse" then "false"
+          elif $type == "TermTypeIdentity" then "."
+          elif $type == "TermTypeUnary" then .unary | "\(.op)\({term: .term} | _f)"
+          elif $type == "TermTypeIndex" then .index | _index
+          elif $type == "TermTypeFunc" then "\(.func.name)\(
+            if .func.args then
+              [.func.args.[] | _f] | join(", ") | "(\(.))"
+            else
+              ""
+            end
+          )"
+          elif $type == "TermTypeObject" then
+            ( .object.key_vals
+            | "{\(
+              [ .[] |
+                "\(
+                  if .key then .key
+                  elif .key_string then .key_string.str | tojson
+                  else .key_query | _f
+                  end
+                )\(
+                  if .val then 
+                    ": \([.val.queries.[] | _f] | join(", "))"
+                  else ""
+                  end
+                )"
+              ] | join(", ")
+            )}" )
+          elif $type == "TermTypeArray" then  "[\(.array.query | _f)]"
+          elif $type == "TermTypeIf" then .if |
+            "if \(.cond | _f) then \(.then | _f) \(
+              if .elif then [
+                .elif.[] |
+                "elif \(.cond | _f) then \(.then | _f) "
+              ] | join("")
+              else ""
+              end
+            )else \(.else | _f) end"
+          elif $type == "TermTypeReduce" then .reduce |
+            "reduce \({term: .term} | _f) as \(.pattern | _pattern) (\(.start | _f);\(.update | _f))"
+          elif $type == "TermTypeForeach" then .foreach |
+            "foreach \({term: .term} | _f) as \(.pattern | _pattern) (\(.start | _f);\(.update | _f)\(
+              if .extract then ";\(.extract | _f)" else "" end
+            ))"
+          elif $type == "TermTypeQuery" then "(\(.query | _f))"
+          elif $type == "TermTypeFormat" then "\(.format) \(.str)" 
+          elif $type == "TermTypeTry" then .try |
+            "try \(.body | _f)\(if .catch then " catch \(.catch | _f)" else "" end)" 
+          else error("unsupported term: \(.)")
+          end
+        )\(
+          if .suffix_list then
+            [
+              .suffix_list[] |
+              if .index then .index | _index
+              elif .bind then .bind | "as \([.patterns[] | _pattern] | join(", ")) | \(.body | _f)"
+              elif .iter then "[]"
+              elif .optional then "?"
+              else error("unsupported suffix type: \(.)")
+              end
+            ] | join("")
+          else ""
+          end
+        )"
+      elif $op then
+        (if $op | . == "," then "" else " " end) as $pad
+        | "\(.left | _f)\($pad)\($op) \(.right | _f)"
+      else error("unsupported query: \(.)")
+      end;
+  [_f] | join("");
+
 def _builtins_src: "
 def debug(msgs): (msgs | debug | empty), .;
 def halt_error: halt_error(5);

From c2951babb896f8cb041b654ddecf04855aa84aec Mon Sep 17 00:00:00 2001
From: Miguel Ceriani <miguel.ceriani@gmail.com>
Date: Tue, 15 Apr 2025 17:17:19 +0200
Subject: [PATCH 2/3] Add test for serialization and fix mapping of function
 args

---
 jqjq.jq | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/jqjq.jq b/jqjq.jq
index caf6a14..a8b45d3 100644
--- a/jqjq.jq
+++ b/jqjq.jq
@@ -2113,7 +2113,7 @@ def ast_tostring:
           if $func_defs then [
             $func_defs.[]
             | "def \(.name)\(
-              if .args then "(\(.args | join(", ")))"
+              if .args then "(\(.args | join("; ")))"
               else ""
               end
             ): \(.body | _f); "
@@ -2142,7 +2142,7 @@ def ast_tostring:
           elif $type == "TermTypeIndex" then .index | _index
           elif $type == "TermTypeFunc" then "\(.func.name)\(
             if .func.args then
-              [.func.args.[] | _f] | join(", ") | "(\(.))"
+              [.func.args.[] | _f] | join("; ") | "(\(.))"
             else
               ""
             end
@@ -2762,6 +2762,7 @@ def usage:
   + "  --jq PATH                 jq implementation to run with\n"
   + "  --lex                     Lex EXPR\n"
   + "  --parse                   Lex then parse EXPR\n"
+  + "  --serialize               Expect an AST in EXPR and serialize it as jq\n"
   + "  --repl                    REPL\n"
   + "  --no-builtins             Don't include builtins\n"
   + "\n"
@@ -2888,6 +2889,7 @@ def parse_options:
     // option(null; "repl"; .mode = "repl")
     // option(null; "lex"; .mode = "lex")
     // option(null; "parse"; .mode = "parse")
+    // option(null; "serialize"; .mode = "serialize")
     // option(null; "no-builtins"; .no_builtins = true)
     //
       ( if .args.is_short then "-\(.args.curr[:1])" else "--\(.args.curr)" end
@@ -3066,7 +3068,7 @@ def jqjq($args; $env):
     , "\n" # input interrupted so no line entered
     );
 
-  def _run_tests:
+  def _run_tests($testSerialize):
     # read jq test format:
     # # comment
     # expr
@@ -3151,7 +3153,10 @@ def jqjq($args; $env):
       | "line \(.line): \(.input | tojson) | \(.expr) -> \(.output | _to_unslurped)" as $test_name
       | . as $test
       | try
-          ( ($test.expr | lex | parse) as $ast
+          ( (
+              ($test.expr | lex | parse)
+              | if $testSerialize then ast_tostring | lex| parse else . end
+            ) as $ast
           | $test.input
           | [ eval_ast(
                 $ast;
@@ -3246,8 +3251,10 @@ def jqjq($args; $env):
   | if $opts.action == "help"        then usage
     elif $opts.mode == "lex"         then $opts.program | lex, "\n"
     elif $opts.mode == "parse"       then $opts.program | lex | parse, "\n"
+    elif $opts.mode == "serialize"   then $opts.program | ast_tostring, "\n"
     elif $opts.mode == "repl"        then _repl($opts)
-    elif $opts.action == "run-tests" then input | _run_tests
+    elif $opts.action == "run-tests-without-serialize" then input | _run_tests(false)
+    elif $opts.action == "run-tests" then input | (_run_tests(false), _run_tests(true))
     else _filter($opts)
     end
   );

From 2411113cd8a2c641df54c6981e729f782754248e Mon Sep 17 00:00:00 2001
From: Miguel Ceriani <miguel.ceriani@gmail.com>
Date: Tue, 15 Apr 2025 22:44:33 +0200
Subject: [PATCH 3/3] Fix all errors found with tests

---
 jqjq.jq | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/jqjq.jq b/jqjq.jq
index a8b45d3..6ba0ac6 100644
--- a/jqjq.jq
+++ b/jqjq.jq
@@ -2094,22 +2094,35 @@ def ast_tostring:
   def _pattern:
     if .name then .name
     elif .array then "[\([.array[] | _pattern] | join(", "))]"
-    elif .object then "{\([.object[] | "\(.key)\(if .val then ": \(.val | _pattern)" else "" end)"] | join(", "))}"
+    elif .object then
+      "{\(
+        [.object[] | "\(
+          if .key then .key else .key_string.str | tojson end
+        )\(
+          if .val then ": \(.val | _pattern)" else "" end
+        )"] |
+        join(", ")
+      )}"
     else error("unsupported type of pattern: \(.)")
     end;
   def _f:
     def _index:
       ".\(
-        if .start then
-          "[\(.start | _f)\(if .end then ":\(.end | _f)" else "" end)]"
+        if .start or .is_slice then
+          "[\(
+            if .start then .start | _f else "" end
+          )\(
+            if .is_slice then ":" else "" end
+          )\(
+            if .end then .end | _f else "" end
+          )]"
         elif .name then .name
         elif .str then .str.str | tojson
         else error("unsupported type of index: \(.)")
         end
       )";
     . as {term: {type: $type}, $op, $func_defs}
-    | if $type then .term |
-        "\(
+    | "\(
           if $func_defs then [
             $func_defs.[]
             | "def \(.name)\(
@@ -2120,7 +2133,9 @@ def ast_tostring:
           ] | join("")
           else ""
           end
-        )\(
+    )\(
+      if $type then .term |
+        "\(
           if $type == "TermTypeNull" then "null"
           elif $type == "TermTypeNumber" then .number | tostring
           elif $type == "TermTypeString" then
@@ -2164,7 +2179,7 @@ def ast_tostring:
                 )"
               ] | join(", ")
             )}" )
-          elif $type == "TermTypeArray" then  "[\(.array.query | _f)]"
+          elif $type == "TermTypeArray" then .array | "[\(if .query then .query | _f else "" end)]"
           elif $type == "TermTypeIf" then .if |
             "if \(.cond | _f) then \(.then | _f) \(
               if .elif then [
@@ -2173,7 +2188,7 @@ def ast_tostring:
               ] | join("")
               else ""
               end
-            )else \(.else | _f) end"
+            )\(if .else then " else \(.else | _f)" else "" end) end"
           elif $type == "TermTypeReduce" then .reduce |
             "reduce \({term: .term} | _f) as \(.pattern | _pattern) (\(.start | _f);\(.update | _f))"
           elif $type == "TermTypeForeach" then .foreach |
@@ -2181,7 +2196,7 @@ def ast_tostring:
               if .extract then ";\(.extract | _f)" else "" end
             ))"
           elif $type == "TermTypeQuery" then "(\(.query | _f))"
-          elif $type == "TermTypeFormat" then "\(.format) \(.str)" 
+          elif $type == "TermTypeFormat" then "\(.format) \(.str | _f)" 
           elif $type == "TermTypeTry" then .try |
             "try \(.body | _f)\(if .catch then " catch \(.catch | _f)" else "" end)" 
           else error("unsupported term: \(.)")
@@ -2191,7 +2206,7 @@ def ast_tostring:
             [
               .suffix_list[] |
               if .index then .index | _index
-              elif .bind then .bind | "as \([.patterns[] | _pattern] | join(", ")) | \(.body | _f)"
+              elif .bind then .bind | " as \([.patterns[] | _pattern] | join(", ")) | \(.body | _f)"
               elif .iter then "[]"
               elif .optional then "?"
               else error("unsupported suffix type: \(.)")
@@ -2204,7 +2219,8 @@ def ast_tostring:
         (if $op | . == "," then "" else " " end) as $pad
         | "\(.left | _f)\($pad)\($op) \(.right | _f)"
       else error("unsupported query: \(.)")
-      end;
+      end
+    )";
   [_f] | join("");
 
 def _builtins_src: "