support REPL modes

src/worker.jl

@@ -396,6 +396,34 @@ function worker_init(f::File)
             line::Integer,
         )
             loc = LineNumberNode(line, Symbol(file))
+
+            # inspired by IJulia/execute_request()
+            # a cell beginning with "? ..." is interpreted as a help request
+            hcode = replace(code, r"^\s*\?" => "")
+            if hcode != code
+                code = string(
+                    "import REPL; Core.eval(REPL, REPL.helpmode(\"",
+                    chomp(hcode),
+                    "\"))",
+                )
+            end
+
+            # "; ..." cells are interpreted as shell commands for run
+            hcode = replace(code, r"^\s*;" => "")
+            if hcode != code
+                code = string("Base.repl_cmd(`", chomp(hcode), "`, stdout)")
+            end
+
+            # "] ..." cells are interpreted as pkg shell commands
+            hcode = replace(code, r"^\]" => "")
+            if hcode != code
+                code = string(
+                    "Pkg.REPLMode.PRINTED_REPL_WARNING[]=true; Pkg.REPLMode.do_cmd(Pkg.REPLMode.MiniREPL(),\"",
+                    chomp(hcode),
+                    "\")",
+                )
+            end
+
             try
                 ast = _parseall(code, filename = file, lineno = line)
                 @assert Meta.isexpr(ast, :toplevel)

test/Project.toml

@@ -3,6 +3,7 @@ JSON3 = "0f8b85d8-7281-11e9-16c2-39a750bddbf1"
 JSONSchema = "7d188eb4-7ad8-530c-ae41-71a32a6d4692"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
 NodeJS_18_jll = "c1e1d063-8311-5f52-a749-c7b05e91ae37"
+REPL = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
 Sockets = "6462fe0b-24de-5631-8697-dd941f90decc"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 quarto_jll = "b7163347-bfae-5fd9-aba4-19f139889d78"

test/examples/repl_modes.qmd

@@ -0,0 +1,15 @@
+---
+title: REPL modes
+---
+
+```{julia}
+;echo OK
+```
+
+```{julia}
+] status
+```
+
+```{julia}
+?Int64
+```

test/testsets/repl_modes.jl

@@ -0,0 +1,33 @@
+include("../utilities/prelude.jl")
+
+test_example(joinpath(@__DIR__, "../examples/repl_modes.qmd")) do json
+
+    cells = json["cells"]
+    @test length(cells) == 6
+
+    cell = cells[2]
+    @test cell["outputs"][1]["text"] == "OK\n"
+    @test cell["outputs"][1]["output_type"] == "stream"
+    @test cell["outputs"][1]["name"] == "stdout"
+
+    cell = cells[4]
+    @test cell["outputs"][1]["output_type"] == "stream"
+    @test cell["outputs"][1]["name"] == "stdout"
+    @test contains(cell["outputs"][1]["text"], "Status")
+    @test contains(cell["outputs"][1]["text"], "Project.toml")
+
+    cell = cells[6]
+    @test cell["outputs"][1]["output_type"] == "stream"
+    @test cell["outputs"][1]["name"] == "stdout"
+    @test contains(cell["outputs"][1]["text"], "search")
+
+    @test cell["outputs"][2]["output_type"] == "execute_result"
+    @test contains(cell["outputs"][2]["data"]["text/plain"], "64-bit signed integer type")
+    @test contains(
+        cell["outputs"][2]["data"]["text/markdown"],
+        "64-bit signed integer type",
+    )
+    @test contains(cell["outputs"][2]["data"]["text/html"], "64-bit signed integer type")
+    @test contains(cell["outputs"][2]["data"]["text/latex"], "64-bit signed integer type")
+
+end