fix(emitter): loop in expression context via needsValue + IIFE wrapper

- Add needsValue parameter to emitExpr/emitSpecialForm to track expression context
- loop wraps in (proc(): CljVal = ... )() when needsValue=true
- Function call args, let/def values, vector/map literals pass needsValue=true
- emitProgramInternal passes needsValue=isLast for top-level forms
- Fixes: loop as function arg, loop in let RHS, loopResult at top level

.gitignore

@@ -26,3 +26,4 @@ test_single_debug.py
 src/tui_config
 experiments/native-lib/test_client/test_client
 experiments/wasm/tools/zig/
+lib/bring_http.nim

src/emitter.nim

@@ -126,7 +126,7 @@ proc isLocalVar(name: string): bool =
       return true
   return false
 
-proc emitExpr*(v: CljVal, indent: int = 0): string
+proc emitExpr*(v: CljVal, indent: int = 0, needsValue: bool = false): string
 proc emitBlock*(items: seq[CljVal], indent: int, useResult: bool = false): string
 proc emitQuotedForm*(v: CljVal): string
 proc emitFnAsProc*(items: seq[CljVal], indent: int): string
@@ -481,7 +481,7 @@ proc letDestructuredBindings(bindings: CljVal): CljVal =
     i += 2
   return cljVector(result)
 
-proc emitSpecialForm(items: seq[CljVal], indent: int): string =
+proc emitSpecialForm(items: seq[CljVal], indent: int, needsValue: bool = false): string =
   let sp = indentStr(indent)
   let head = items[0]
   if head.kind != ckSymbol:
@@ -494,7 +494,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
     # Head is not a symbol - evaluate as function call: ((fn ...) args...)
     var argParts: seq[string] = @[]
     for i in 1..<items.len:
-      argParts.add(emitExpr(items[i], indent))
+      argParts.add(emitExpr(items[i], indent, needsValue = true))
     let fnCode = emitExpr(head, 0)
     return sp & "cljApply(" & fnCode & ", cljList(@[" & argParts.join(", ") & "]))"
   let op = resolveNsAlias(head.symName)
@@ -695,7 +695,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
       if nameItem.kind == ckSymbol:
         let mangled = mangleName(nameItem.symName)
         registerGlobal(nameItem.symName)
-        let valCode = emitExpr(valItem, 0)
+        let valCode = emitExpr(valItem, 0, needsValue = true)
         return sp & "let " & mangled & " = " & valCode
       return sp & "cljNil()"
     var name = items[1]
@@ -720,7 +720,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
         let valCode = emitFnAsProc(valForm.items, 0)
         emitLibMode = oldEmitLibMode
         return sp & "let " & mangled & " = " & valCode
-      let valCode = emitExpr(items[2], 0)
+      let valCode = emitExpr(items[2], 0, needsValue = true)
       return sp & "let " & mangled & " = " & valCode
     else:
       # For nested def: use global var so it's accessible from closures
@@ -730,7 +730,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
         let valCode = emitFnAsProc(valForm.items, indent)
         emitLibMode = oldEmitLibMode
         return sp & "var " & mangled & " = " & valCode.strip() & "\n" & sp & mangled
-      let valCode = emitExpr(items[2], indent)
+      let valCode = emitExpr(items[2], indent, needsValue = true)
       return sp & "var " & mangled & " = " & valCode.strip() & "\n" & sp & mangled
 
   of "defn":
@@ -1038,7 +1038,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
       if bname.kind != ckSymbol:
         raise newException(EmitterError, "let binding name must be a symbol, got " & $bname.kind & ": " & $bname)
       addToScope(bname.symName)
-      let bcode = emitExpr(bval, indent + 1)
+      let bcode = emitExpr(bval, indent + 1, needsValue = true)
       if bcode.find("\n") != -1:
         # Multi-line value: use var and place first line on next line for correct indentation
         lines.add(indentStr(indent + 1) & "var " & mangleName(bname.symName) & ": CljVal")
@@ -1208,7 +1208,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
         lname = lname.items[1]
       if lname.kind != ckSymbol:
         raise newException(EmitterError, "loop binding name must be a symbol")
-      loopParams.add((mangleName(lname.symName), lname.symName, emitExpr(lval, 0)))
+      loopParams.add((mangleName(lname.symName), lname.symName, emitExpr(lval, 0, needsValue = true)))
       li += 2
     var loopVars: seq[string] = @[]
     var lines: seq[string] = @[]
@@ -1273,7 +1273,17 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
     if needsResultVar:
       lines.add(sp & "loopResult")
       loopResultVar = ""
-    return lines.join("\n")
+    let loopCode = lines.join("\n")
+    if needsValue:
+      # Wrap in IIFE for expression contexts (function args, let RHS, etc.)
+      var iifeLines: seq[string] = @[]
+      iifeLines.add(sp & "(proc(): CljVal =")
+      iifeLines.add(indentCode(loopCode, 1))
+      if not needsResultVar:
+        iifeLines.add(indentStr(indent + 1) & "cljNil()")
+      iifeLines.add(sp & ")()")
+      return iifeLines.join("\n")
+    return loopCode
 
   of "recur":
     if items.len < 2:
@@ -1749,7 +1759,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
       return sp & "cljNil()"
     var argParts: seq[string] = @[]
     for i in 2..<items.len:
-      argParts.add(emitExpr(items[i], indent))
+      argParts.add(emitExpr(items[i], indent, needsValue = true))
     let mangled = mangleName(className.symName)
     return sp & mangled & "(" & argParts.join(", ") & ")"
 
@@ -2077,7 +2087,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
     if rn.len > 0:
       var argParts: seq[string] = @[]
       for i in 1..<items.len:
-        argParts.add(emitExpr(items[i], indent))
+        argParts.add(emitExpr(items[i], indent, needsValue = true))
       # Variadic functions take seq[CljVal]
       let variadic = op in ["+", "-", "*", "/", "=", ">", "<", ">=", "<=", "not=",
                              "println", "prn", "print", "str", "pr-str",
@@ -2163,7 +2173,7 @@ proc emitQuotedForm*(v: CljVal): string =
   else:
     return emitExpr(v, 0)
 
-proc emitExpr*(v: CljVal, indent: int = 0): string =
+proc emitExpr*(v: CljVal, indent: int = 0, needsValue: bool = false): string =
   let sp = indentStr(indent)
   case v.kind
   of ckNil:
@@ -2237,12 +2247,12 @@ proc emitExpr*(v: CljVal, indent: int = 0): string =
     # Macro-expand before emitting
     let expanded = macroexpand(v)
     if expanded == v:
-      return emitSpecialForm(v.items, indent)
+      return emitSpecialForm(v.items, indent, needsValue)
-    return emitExpr(expanded, indent)
+    return emitExpr(expanded, indent, needsValue)
   of ckVector:
     var parts: seq[string] = @[]
     for item in v.items:
-      parts.add(emitExpr(item, indent))
+      parts.add(emitExpr(item, indent, needsValue = true))
     return sp & "cljVector(@[" & parts.join(", ") & "])"
   of ckMap:
     if v.mapKeys.len == 0:
@@ -2250,18 +2260,18 @@ proc emitExpr*(v: CljVal, indent: int = 0): string =
     var keyParts: seq[string] = @[]
     var valParts: seq[string] = @[]
     for i in 0..<v.mapKeys.len:
-      keyParts.add(emitExpr(v.mapKeys[i], indent))
+      keyParts.add(emitExpr(v.mapKeys[i], indent, needsValue = true))
-      valParts.add(emitExpr(v.mapVals[i], indent))
+      valParts.add(emitExpr(v.mapVals[i], indent, needsValue = true))
     return sp & "cljMap(@[" & keyParts.join(", ") & "], @[" & valParts.join(", ") & "])"
   of ckSet:
     var parts: seq[string] = @[]
     for item in v.setItems:
-      parts.add(emitExpr(item, indent))
+      parts.add(emitExpr(item, indent, needsValue = true))
     return sp & "cljSet(@[" & parts.join(", ") & "])"
   of ckFn:
     return sp & "cljFn(proc(args: seq[CljVal]): CljVal = discard cljNil())"
   of ckAtom:
-    return sp & "cljAtom(" & emitExpr(v.atomVal, 0) & ")"
+    return sp & "cljAtom(" & emitExpr(v.atomVal, 0, needsValue = true) & ")"
   of ckTransient:
     return sp & "cljTransient(cljNil())"
   of ckAgent:
@@ -2356,7 +2366,7 @@ proc emitProgramInternal(forms: seq[CljVal]): string =
       let defCode = emitExpr(ef, 0)
       defs.add(defCode)
     else:
-      let code = emitExpr(ef, 2)
+      let code = emitExpr(ef, 2, needsValue = isLast)
       let stripped = code.strip()
       if stripped.startsWith("echo ") or stripped.startsWith("discard ") or
          stripped.startsWith("var ") or stripped.startsWith("while ") or