diff --git a/src/grammar/expenses.l b/src/grammar/expenses.l
new file mode 100644
index 0000000..c3aa604
--- /dev/null
+++ b/src/grammar/expenses.l
@@ -0,0 +1,30 @@
+/* expenses.l: Expenses lexical analysis file
+*/
+
+%{
+#include <stdio.h>
+#include <glib.h>
+#include "../../src/grammar/types.h"
+#include "expenses.tab.h"
+%}
+                        
+DIGIT    [0-9]
+
+%%
+
+{DIGIT}+                yylval.res=atoi(yytext); return TOK_INT;
+{DIGIT}+"."{DIGIT}*     yylval.val=atof(yytext); return TOK_DOUBLE;
+"-"|out|spesa           yylval.cmd=BOT_CMD_OUT; return TOK_CMD_OUT;
+"+"|in|ricavo           yylval.cmd=BOT_CMD_IN; return TOK_CMD_IN;
+del|storno              yylval.cmd=BOT_CMD_DELETE; return TOK_CMD_DEL;
+report                  yylval.cmd=BOT_CMD_REPORT; return TOK_CMD_REPORT;
+daily                   yylval.tsp=BOT_TS_DAILY; return TOK_TS_DAILY;
+weekly                  yylval.tsp=BOT_TS_WEEKLY; return TOK_TS_WEEKLY;
+monthly                 yylval.tsp=BOT_TS_MONTHLY; return TOK_TS_MONTHLY;
+yearly                  yylval.tsp=BOT_TS_YEARLY; return TOK_TS_YEARLY;
+[a-zA-Z0-9_]+           yylval.str=g_string_new(yytext); return TOK_USER; /* user can't have special characters */
+\"[^\n]+\"              yylval.str=g_string_new(yytext); return TOK_STR;  /* anything excepts '\n'; needs to be at the bottom of flex rules here */
+[ \t]+                  /* ignore whitespace */;
+\n                      /* ignore end of line */;
+
+%%
diff --git a/src/grammar/expenses.y b/src/grammar/expenses.y
new file mode 100644
index 0000000..b1e0769
--- /dev/null
+++ b/src/grammar/expenses.y
@@ -0,0 +1,72 @@
+%{
+#include <stdio.h>
+#include <glib.h>  /* For GString */
+#include "../../src/grammar/types.h"
+
+/* suppress warning about missing declarations */
+int yylex();
+int yyparse();
+
+void yyerror(const char *str)
+{
+    fprintf(stderr,"error: %s\n",str);
+}
+
+int yywrap()
+{
+    return 1;
+} 
+
+%}
+
+%define parse.lac full
+%define parse.error verbose
+
+%union {
+    int res;                     /* return value of C procedure */
+    double val;                  /* For returning numbers.                   */
+    BotCommand cmd;
+    BotReportTimespan tsp;
+    GString *str;
+}
+
+%token  <res>  TOK_INT
+%token  <val>  TOK_DOUBLE 
+%token  <cmd>  TOK_CMD_IN TOK_CMD_OUT TOK_CMD_DEL TOK_CMD_REPORT       
+%token  <tsp>  TOK_TS_DAILY TOK_TS_WEEKLY TOK_TS_MONTHLY TOK_TS_YEARLY
+%token  <str>  TOK_USER      /* string for user */
+%token  <str>  TOK_STR       /* string for notes */
+%type   <cmd>  update;
+%type   <val>  value;
+%type   <tsp>  ts;
+%type   <res>  msg;
+
+%%
+input:    /* empty */
+        | input line
+;
+
+line:     '\n'
+        | msg
+        | error { yyerrok; }
+;
+
+msg:      update value TOK_USER TOK_STR       { printf("update: %d %f %s %s\n", $1, $2, $3->str, $4->str); $$ = 0;}
+        | TOK_CMD_DEL TOK_INT                 { printf("delete: %d\n", $2); $$ = 0; }
+        | TOK_CMD_REPORT ts                   { printf("report: %d\n", $2); $$ = 0; }
+
+value:    TOK_INT                             { $$ = (double)$1; } 
+        | TOK_DOUBLE
+        ;
+
+update:   TOK_CMD_IN
+        | TOK_CMD_OUT
+;
+
+ts:       TOK_TS_DAILY
+        | TOK_TS_WEEKLY
+        | TOK_TS_MONTHLY
+        | TOK_TS_YEARLY
+;
+%%
+
diff --git a/src/grammar/types.h b/src/grammar/types.h
new file mode 100644
index 0000000..716dd38
--- /dev/null
+++ b/src/grammar/types.h
@@ -0,0 +1,17 @@
+/* additional types for expenses
+ */
+#pragma once
+
+typedef enum BotCommand {
+    BOT_CMD_IN,
+    BOT_CMD_OUT,
+    BOT_CMD_DELETE,
+    BOT_CMD_REPORT
+} BotCommand;
+
+typedef enum BotReportTimespan {
+    BOT_TS_DAILY,
+    BOT_TS_WEEKLY,
+    BOT_TS_MONTHLY,
+    BOT_TS_YEARLY
+} BotReportTimespan;