diff --git a/devshell/default.nix b/devshell/default.nix
index 46cb4f8..fd07a4f 100644
--- a/devshell/default.nix
+++ b/devshell/default.nix
@@ -1,24 +1,33 @@
-{
+{ 
   system,
   pkgs,
   self 
-}: pkgs.mkShell {
-  buildInputs =
-    (with self.packages.${system}; [
-      nvim-alias
-      #prettify-log
-      nvim-pager
-    ])
-    ++ (with pkgs; [
-      git
-      jq
-      yq-go
-      curl
-      (writeScriptBin "hemar-check" ''
-        ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null vm-postgres 'zsh -c check'
-      '')
-    ]);
-
-  # environment
-  PAGER = "${self.packages.${system}.nvim-pager}/bin/pager";
+}: 
+(import ./dev { inherit self system pkgs; }) 
+// {
+  c          = import ./c.nix          { inherit self system pkgs; };
+  postgres-c = import ./postgres-c.nix { inherit self system pkgs; };
+  pure-c     = import ./pure-c.nix     { inherit self system pkgs; };
+  rust       = import ./rust.nix       { inherit self system pkgs; };
+  haskell    = import ./haskell.nix    { inherit self system pkgs; };
+  default    = pkgs.mkShell {
+    buildInputs =
+      (with self.packages.${system}; [
+        nvim-alias
+        #prettify-log
+        nvim-pager
+      ])
+      ++ (with pkgs; [
+        git
+        jq
+        yq-go
+        curl
+        #(writeScriptBin "hemar-check" ''
+        #  ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null vm-postgres 'zsh -c check'
+        #'')
+      ]);
+  
+    # environment
+    PAGER = "${self.packages.${system}.nvim-pager}/bin/pager";
+  };
 }
diff --git a/devshell/dev/default.nix b/devshell/dev/default.nix
new file mode 100644
index 0000000..bd9c4ba
--- /dev/null
+++ b/devshell/dev/default.nix
@@ -0,0 +1,7 @@
+{
+  system,
+  self,
+  pkgs
+}: {
+  hemar      = import ./hemar.nix      { inherit self system pkgs; };
+}
diff --git a/devshell/dev/hemar.nix b/devshell/dev/hemar.nix
new file mode 100644
index 0000000..f4075bb
--- /dev/null
+++ b/devshell/dev/hemar.nix
@@ -0,0 +1,5 @@
+{ pkgs, ... }: pkgs.mkShell {
+  buildInputs = (with pkgs; [
+    dash
+  ]);
+}
diff --git a/flake.nix b/flake.nix
index 856d997..26799c7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -40,36 +40,27 @@
     rust-overlay,
     ...
   }@inputs: let
-    flake = ./.;
-    nixpkgs = nixpkgs-25-05;
+    flake    = ./.;
+    nixpkgs  = nixpkgs-25-05;
     overlays = [ self.overlays.default ];
     self-lib = import ./lib { inherit flake self inputs; };
   in self-lib.forAllSystemsWithPkgs ([(import rust-overlay)] ++ overlays) ({
     system,
     pkgs,
   }: {
-    packages.${system} = import ./package { inherit system pkgs self; };
-
-    legacyPackages.${system} =  import nixpkgs { inherit system overlays; };
-
-    devShells.${system} = {
-      c          = import ./devshell/c.nix          { inherit self system pkgs; };
-      postgres-c = import ./devshell/postgres-c.nix { inherit self system pkgs; };
-      pure-c     = import ./devshell/pure-c.nix     { inherit self system pkgs; };
-      default    = import ./devshell/default.nix    { inherit self system pkgs; };
-      rust       = import ./devshell/rust.nix       { inherit self system pkgs; };
-      haskell    = import ./devshell/haskell.nix    { inherit self system pkgs; };
-    };
+    packages.${system}         = import ./package      { inherit system pkgs self; };
+    legacyPackages.${system}   = import nixpkgs        { inherit system overlays; };
+    devShells.${system}        = import ./devshell     { inherit self system pkgs; };
     nixosConfigurations = {
       "devvm-manual|${system}" = import ./nixos/system/devvm-manual/default.nix 
         { inherit flake self inputs system; };
-      "devvm-hemar|${system}" = import ./nixos/system/devvm-hemar/default.nix 
+      "devvm-hemar|${system}"  = import ./nixos/system/devvm-hemar/default.nix 
         { inherit flake self inputs system; };
     };
   }) // {
     lib = self-lib;
-    overlays.default = import ./overlay      { inherit flake self inputs nixpkgs; };
-    nixosModules     = import ./nixos/module { inherit flake self inputs nixpkgs; };
-    templates        = import ./template     { inherit flake self inputs nixpkgs; };
+    overlays.default           = import ./overlay      { inherit flake self inputs nixpkgs; };
+    nixosModules               = import ./nixos/module { inherit flake self inputs nixpkgs; };
+    templates                  = import ./template     { inherit flake self inputs nixpkgs; };
   };
 }
diff --git a/package/c/hemar/.gitignore b/package/c/hemar-legacy/.gitignore
similarity index 100%
rename from package/c/hemar/.gitignore
rename to package/c/hemar-legacy/.gitignore
diff --git a/package/c/hemar/Makefile b/package/c/hemar-legacy/Makefile
similarity index 100%
rename from package/c/hemar/Makefile
rename to package/c/hemar-legacy/Makefile
diff --git a/package/c/hemar/default.nix b/package/c/hemar-legacy/default.nix
similarity index 100%
rename from package/c/hemar/default.nix
rename to package/c/hemar-legacy/default.nix
diff --git a/package/c/hemar/hemar--0.1.sql b/package/c/hemar-legacy/hemar--0.1.sql
similarity index 100%
rename from package/c/hemar/hemar--0.1.sql
rename to package/c/hemar-legacy/hemar--0.1.sql
diff --git a/package/c/hemar/hemar.c b/package/c/hemar-legacy/hemar.c
similarity index 100%
rename from package/c/hemar/hemar.c
rename to package/c/hemar-legacy/hemar.c
diff --git a/package/c/hemar/hemar.control b/package/c/hemar-legacy/hemar.control
similarity index 100%
rename from package/c/hemar/hemar.control
rename to package/c/hemar-legacy/hemar.control
diff --git a/package/c/hemar/hemar.h b/package/c/hemar-legacy/hemar.h
similarity index 100%
rename from package/c/hemar/hemar.h
rename to package/c/hemar-legacy/hemar.h
diff --git a/package/c/hemar/make.sh b/package/c/hemar-legacy/make.sh
similarity index 100%
rename from package/c/hemar/make.sh
rename to package/c/hemar-legacy/make.sh
diff --git a/package/c/hemar/postgreact--1.0.sql b/package/c/hemar-legacy/postgreact--1.0.sql
similarity index 100%
rename from package/c/hemar/postgreact--1.0.sql
rename to package/c/hemar-legacy/postgreact--1.0.sql
diff --git a/package/c/hemar/postgreact.control.in b/package/c/hemar-legacy/postgreact.control.in
similarity index 100%
rename from package/c/hemar/postgreact.control.in
rename to package/c/hemar-legacy/postgreact.control.in
diff --git a/package/c/hemar/postgreact.h b/package/c/hemar-legacy/postgreact.h
similarity index 100%
rename from package/c/hemar/postgreact.h
rename to package/c/hemar-legacy/postgreact.h
diff --git a/package/c/hemar/test/mod.sql b/package/c/hemar-legacy/test/mod.sql
similarity index 100%
rename from package/c/hemar/test/mod.sql
rename to package/c/hemar-legacy/test/mod.sql
diff --git a/package/c/hemar/test/test_jsonb_path.sql b/package/c/hemar-legacy/test/test_jsonb_path.sql
similarity index 100%
rename from package/c/hemar/test/test_jsonb_path.sql
rename to package/c/hemar-legacy/test/test_jsonb_path.sql
diff --git a/package/c/hemar/test/test_render_all.sql b/package/c/hemar-legacy/test/test_render_all.sql
similarity index 100%
rename from package/c/hemar/test/test_render_all.sql
rename to package/c/hemar-legacy/test/test_render_all.sql
diff --git a/package/c/hemar/test/test_render_exec.sql b/package/c/hemar-legacy/test/test_render_exec.sql
similarity index 100%
rename from package/c/hemar/test/test_render_exec.sql
rename to package/c/hemar-legacy/test/test_render_exec.sql
diff --git a/package/c/hemar/test/test_render_include.sql b/package/c/hemar-legacy/test/test_render_include.sql
similarity index 100%
rename from package/c/hemar/test/test_render_include.sql
rename to package/c/hemar-legacy/test/test_render_include.sql
diff --git a/package/c/hemar/test/test_render_interpolate.sql b/package/c/hemar-legacy/test/test_render_interpolate.sql
similarity index 100%
rename from package/c/hemar/test/test_render_interpolate.sql
rename to package/c/hemar-legacy/test/test_render_interpolate.sql
diff --git a/package/c/hemar/test/test_render_section.sql b/package/c/hemar-legacy/test/test_render_section.sql
similarity index 100%
rename from package/c/hemar/test/test_render_section.sql
rename to package/c/hemar-legacy/test/test_render_section.sql
diff --git a/package/c/hemar/test/test_template_parser.sql b/package/c/hemar-legacy/test/test_template_parser.sql
similarity index 100%
rename from package/c/hemar/test/test_template_parser.sql
rename to package/c/hemar-legacy/test/test_template_parser.sql
diff --git a/package/hemar/hemar.sh b/package/hemar/hemar.sh
new file mode 100644
index 0000000..1d5b827
--- /dev/null
+++ b/package/hemar/hemar.sh
@@ -0,0 +1,130 @@
+#!/bin/dash
+
+# 0 - text
+# 1 - deside tag type
+# 2 - interpolation
+# 3 - section
+# 4 - include
+# 5 - compute
+STAGE=0
+STAGE_BUFFER="$(mktemp)"
+open_tag_flag=0
+
+# data structure :)
+
+# Type = 0..=5
+#
+# Text = string            # just a text body
+#
+# Interpolation = string   # path to variable 
+#
+# Include = string         # path to include data
+#
+# Section = {
+#   v = string      # item variable name for loop
+#   p = string      # path to array for iteration
+#   b = [Element]   # section body
+#    
+# }
+#
+# End = null
+#
+# Compute = {
+#   l     = string  # programing language
+#   b     = string  # function body
+# }
+#
+# Element = {
+#   t = Type        # element type
+#   b = Text        # element body
+#       | Interpolation 
+#       | Section 
+#       | End 
+#       | Include 
+#       | Compute 
+# }
+#
+# Hemar = {
+#    e = [Element]  # elements array
+#}
+# finds close pattern and store the char to the STAGE_BUFFER
+find_close_pattern() {
+  char="${1:?}"
+  if   [ "${close_tag_flag:?}" -eq 0 ] && [ "$char" = ']' ]; then
+    close_tag_flag=1
+  elif [ "${close_tag_flag:?}" -eq 1 ] && [ "$char" = '}' ]; then
+    close_tag_flag=0
+
+    # removes first and last white spaces from the buffer
+    sed -i 's/[[:space:]]$//g' "$STAGE_BUFFER"
+    sed -i 's/^[[:space:]]//g' "$STAGE_BUFFER"
+    
+    # removes last char from buffer (]) is part of close pattern
+    truncate -s -1 "$STAGE_BUFFER"
+    return 0
+  else
+    printf '%s' "$char" >> "$STAGE_BUFFER"
+  fi
+
+  return 1
+}
+
+# finds open pattern and stores the char to the STAGE_BUFFER
+find_open_pattern() {
+  char="${1:?}"
+  if   [ "${open_tag_flag:?}" -eq 0 ] && [ "$char" = '{' ]; then
+    open_tag_flag=1
+  elif [ "${open_tag_flag:?}" -eq 1 ] && [ "$char" = '[' ]; then
+    open_tag_flag=0
+
+    # removes last char from buffer ({) is part of open pattern
+    truncate -s -1 "$STAGE_BUFFER"
+    return 0
+  else
+    printf '%s' "$char" >> "$STAGE_BUFFER"
+  fi
+
+  return 1
+}
+
+parse() {
+  char="$1"
+
+  case "$STAGE" in
+    0)
+      if find_open_pattern "$char"; then
+	plex_set "$data_pointer"''
+        STAGE=1
+      fi
+      ;;
+    1)
+      if find_close_pattern "$char"; then
+        STAGE=0
+      fi
+      ;;
+    2)
+
+      ;;
+    3)
+    
+      ;;
+    4)
+
+      ;;
+    *)
+
+      ;;
+  esac
+}
+
+# Using dd to read one character at a time
+input=$(cat)
+i=1
+while :; do
+    char=$(printf '%s' "$input" | dd bs=1 skip=$((i-1)) count=1 2>/dev/null)
+    [ -z "$char" ] && break
+
+    parse "$char"
+
+    i=$((i+1))
+done
diff --git a/package/hemar/plex.sh b/package/hemar/plex.sh
new file mode 100644
index 0000000..0ec3b74
--- /dev/null
+++ b/package/hemar/plex.sh
@@ -0,0 +1,77 @@
+#!/bin/dash
+
+#data_size="$(eval printf '%s' "\$$structname" | wc -c)"
+#if [ "$data_size" -ge "$(getconf ARG_MAX)" ]; then
+#    # TODO: handle large text
+#    echo "Data too large for an environment variable"
+#    exit 1
+#fi
+
+plex_set() {
+    local structname key val regex base esc_key regex esc temp
+    structname=$1 key=$2 val=$3
+
+    # construct regex for ancestors
+    regex="^$key="
+
+    base=$key
+    while expr "$base" : '.*\.' >/dev/null; do
+        base=$(printf '%s\n' "$base" | sed 's/\.[^.]*$//')
+        esc=$(printf '%s\n' "$base" | sed 's/\./\\./g')
+        regex="$regex|^$esc="
+    done
+
+    # add descendants
+    esc_key="$(printf '%s\n' "$key" | sed 's/\./\\./g')"
+    regex="$regex|^${esc_key}\."
+
+    # remove old
+    # <plex>=$(printf '%s\n' "$<plex>" | grep -v -E "$regex")
+    temp="$(eval "printf '%s\\n' \"\$$structname\"" | grep -v -E "$regex")"
+    eval "$structname=\"\$temp\""
+
+    # add new
+    eval "$structname=\$(printf '%s\\n%s=%s\\n' \"\$$structname\" \"\$key\" \"\$val\")"
+}
+
+plex_child() {
+    local structname prefix
+    structname=$1 prefix=$2
+
+    eval printf '%s\\n' \"\$"$structname"\" \
+      | grep "^$prefix\." \
+      | sed "s|^$prefix\.||"
+}
+
+plex_val() {
+    local structname key
+    structname=$1 key=$2
+    eval printf '%s\n' \"\$"$structname"\" | grep "^$key=" | cut -d= -f2-
+}
+
+plex_fetch() {
+    local structname key
+    structname=$1 key=$2
+    if eval printf '%s\\n' \"\$"$structname"\" | grep -q "^$key="; then
+      eval printf '%s\\n' \"\$"$structname"\" | grep "^$key=" | cut -d= -f2-
+    else
+      eval printf '%s\\n' \"\$"$structname"\" | grep "^$key\." | sed "s|^$key\.||"
+    fi
+}
+
+plex_push() {
+  local structname prefix val max idx newidx kv
+  structname=${1:?}
+  prefix=${2:?}
+  val=${3:?}
+
+  # find max index
+  max=0
+  for kv in $(plex_fetch "$structname" "$prefix"); do
+      idx=${kv%%=*}
+      [ "$idx" -gt "$max" ] 2>/dev/null && max=$idx
+  done
+
+  newidx=$((max + 1))
+  plex_set "$structname" "$prefix.$newidx" "$val"
+}
diff --git a/package/hemar/test.sh b/package/hemar/test.sh
new file mode 100644
index 0000000..de5a587
--- /dev/null
+++ b/package/hemar/test.sh
@@ -0,0 +1,6 @@
+#!/bin/dash
+
+WORKSPACE="$(cd "$(dirname "$0")" && pwd)"
+
+#. "${WORKSPACE:?}/test/plex.sh"
+. "${WORKSPACE:?}/test/time.sh"
diff --git a/package/hemar/test/plex/time.sh b/package/hemar/test/plex/time.sh
new file mode 100644
index 0000000..a9383ff
--- /dev/null
+++ b/package/hemar/test/plex/time.sh
@@ -0,0 +1,111 @@
+#!/bin/dash
+
+. "${WORKSPACE:?}/plex.sh"
+
+MY_STRUCT=''
+
+math() {
+  awk "BEGIN {print $1}"
+}
+
+elapsed() {
+  local task time count decrease avg
+  task=$1
+  time=$2
+  count=$3
+  decrease=${4:-0}
+  avg=$(math "$time/$count-$decrease")
+
+  printf '\n[%s]\nelapsed %s seconds\n%s per second\n' \
+    "$task" "$avg" "$(math "1/$avg")" >&2
+  printf '%s' "$avg"
+}
+
+set_word_length() {
+  local length
+  length=${1:?}
+
+  # shellcheck disable=SC2183
+  __WORD_OFFSET_PATERN="$(printf '%*s' "$length" | tr ' ' '?')"
+}
+
+UNIQ_8_WORDS_COUNT=1000
+DEFAULT_WORD_LENGTH=8
+set_word_length "$DEFAULT_WORD_LENGTH"
+
+randomword() {
+  local length
+  length=${1:-$DEFAULT_WORD_LENGTH}
+  LC_ALL=C tr -dc 'A-Za-z0-9' </dev/urandom | head -c "$length"
+}
+
+WORDS=$(randomword $((8 * UNIQ_8_WORDS_COUNT)))
+
+new_word() {
+  local prefix
+  prefix=${WORDS%"${WORDS#"$__WORD_OFFSET_PATERN"}"}
+  WORDS=${WORDS#"$__WORD_OFFSET_PATERN"}$prefix
+  printf '%s' "$prefix"
+}
+
+bench_set() {
+  local task depth count wordtime i start key d end
+  task=$1
+  depth=$2
+  count=$3
+  wordtime=$4
+  i=0
+  start=$(date +%s)
+  while [ "$i" -lt "$count" ]; do
+    key=$(new_word)
+    if [ "$depth" -gt 1 ]; then
+      d=1
+      while [ "$d" -lt "$depth" ]; do
+        key="$key.$(new_word)"
+        d=$((d + 1))
+      done
+    fi
+    plex_set 'MY_STRUCT' "$key" "$i"
+    i=$((i + 1))
+  done
+  end=$(date +%s)
+  elapsed "$task" "$((end - start))" "$count" "$(math "$wordtime*$depth")" >/dev/null
+}
+
+DEFAULT_TRIES=1000
+ACCURATE_TRIES=10000
+SUPPER_ACCURATE_TRIES=100000
+
+WORD_CREATE_ACCURACY="$ACCURATE_TRIES"
+BENCH_ACCURACY="$DEFAULT_TRIES"
+
+count="$WORD_CREATE_ACCURACY"
+set_word_length 8
+i=0
+start=$(date +%s)
+while [ "$i" -lt "$count" ]; do
+  new_word >/dev/null
+  i=$((i + 1))
+done
+end=$(date +%s)
+wordtime=$(elapsed 'Word creation' "$((end - start))" "$count")
+
+bench_set 'Set element with depth 1 length 8' 1 "$BENCH_ACCURACY" "$wordtime"
+bench_set 'Set element with depth 2 length 8' 2 "$BENCH_ACCURACY" "$wordtime"
+bench_set 'Set element with depth 3 length 8' 3 "$BENCH_ACCURACY" "$wordtime"
+
+count="$W"
+set_word_length 2
+i=0
+start=$(date +%s)
+while [ "$i" -lt "$count" ]; do
+  new_word >/dev/null
+  i=$((i + 1))
+done
+end=$(date +%s)
+wordtime=$(elapsed 'Word creation' "$((end - start))" "$count")
+
+bench_set 'Set element with depth 1 length 2' 1 "$BENCH_ACCURACY" "$wordtime"
+bench_set 'Set element with depth 2 length 2' 2 "$BENCH_ACCURACY" "$wordtime"
+bench_set 'Set element with depth 3 length 2' 3 "$BENCH_ACCURACY" "$wordtime"
+