feat: working parser for rc shell language

1 files changed, 254 insertions, 0 deletions

diff --git a/sys/cmd/rc/rc.h b/sys/cmd/rc/rc.h
new file mode 100644
index 0000000..ad46a77
--- /dev/null
+++ b/sys/cmd/rc/rc.h
@@ -0,0 +1,254 @@
+#pragma once
+
+#include <u.h>
+#include <libn.h>
+
+#include <errno.h>
+#include <sys/wait.h>
+
+#define alloc(ptr)       ptr = emalloc(sizeof(*ptr))
+
+// -----------------------------------------------------------------------
+// main enums
+
+#define GLOB 0x01
+
+/* TODO: make sure there are no collisions */
+enum
+{
+    /* keywords */
+    Kstart=11,  Kfor, Kin, Kwhile, Kif, Kelse, 
+    Kswitch, Kcase, Kfunc, Ktwiddle, 
+    Kbang, Ksubsh, Kend,
+
+    /* tokens */
+    Aword='w', Aredir='r', Adup='d', Asimple='s', 
+    Aargs='A', Awords='W', Abrace='b', Aparen='p', Asub='S',
+    Apcmd='c', Apipefd='-', Aandand='%', Aoror='@', Acount='#', 
+
+    Atick='`', Apipe = '|',  Adol='$', Aquote='"', Aand='&', 
+    Alparen = '(', Arparen = ')', Albrace='{', Arbrace='}',
+    Asemi=';', Acarot='^', Aeq='=',
+};
+
+enum
+{
+    Rappend = 1,
+    Rwrite  = 2,
+    Rread   = 3,
+    Rhere   = 4,
+    Rdupfd  = 5,
+    Rclose  = 6,
+    Rrdwr   = 7,
+};
+
+// -----------------------------------------------------------------------
+// main types
+
+typedef union  Code    Code;
+typedef struct Word    Word;
+typedef struct List    List;
+typedef struct Var     Var;
+typedef struct Tree    Tree;
+typedef struct Builtin Builtin;
+typedef struct Thread  Thread;
+typedef struct Io      Io;
+
+union Code 
+{
+    int    i;
+    char  *s;
+    void (*f)(void);
+};
+
+struct Word
+{
+    char *word;
+    Word *link;
+};
+
+struct List
+{
+    Word *words;
+    List *link;
+};
+
+struct Var
+{
+    string name;
+    Word   *val;
+    Code   *func;
+    Var    *link;
+};
+
+struct Tree
+{
+    ushort type;
+    uchar  quoted : 1;
+    union {
+        char  *str;
+        struct {
+            ushort type;
+            int fd[2];
+        } redir;
+    };
+
+    Tree *child[3], *link;
+};
+
+struct Builtin
+{
+    char  *cmd;
+    void (*func)(void);
+};
+
+struct Thread
+{
+    Code   *code, *ip;
+    List   *stack;
+    Var    *local;
+    struct {
+        uchar eof : 1;
+        int   line;
+        char *name;
+        Io   *io;
+    } cmd;
+
+    int     pid;
+    Tree   *nodes;
+    Thread *link; /* continuation */
+};
+
+struct Io
+{
+    int   fd;
+    uchar *b, *e, buf[];
+};
+
+// -----------------------------------------------------------------------
+// global interpreter variables
+
+extern Thread *shell;
+extern int     ntrap;
+extern int     status;
+
+extern Io     *errio;
+
+extern Builtin builtins[];
+extern Var    *globals[1021]; /* for now must be prime */
+
+// -----------------------------------------------------------------------
+// interpreter functions (defined in exec.c)
+
+/* 
+ * notation: 
+ * (var1, var2, ...) : items from stack
+ * [var1, var2, ...] : items from code stream
+ *      -> moves value
+ */
+extern void Xmark(void);      /* Xmark: delimit stack with new list */
+extern void Xword(void);      /* Xword[val] -> (val) */
+extern void Xassign(void);    /* Xassign(name, val): assign name to val */
+extern void Xdol(void);       /* Xdol(name): get variable value */
+extern void Xsimple(void);    /* Xsimple(args): run command */
+extern void Xexit(void);      /* Xexit: exit with status */
+extern void Xerror(char *s);  /* Xerror: report an error */
+extern void Xparse(void);
+
+// -----------------------------------------------------------------------
+// shell functions
+
+/* 
+ * util.c 
+ */
+void *emalloc(uintptr size);
+void *erealloc(void *ptr, uintptr size);
+void  efree(void *);
+void  panic(char *msg, int n);
+
+/* 
+ * io.c 
+ */
+Io   *openfd(int fd);
+Io   *openstr(void);
+Io   *opencore(int len, char *s);
+void  rewindio(Io *f);
+void  closeio(Io *f);
+void  flush(Io **fp);
+
+/* reads */
+int   rchr(Io *f);
+
+/* writes */
+int   pchr(Io *f, int c);
+void  pquo(Io *f, char *s);
+void  pwrd(Io *f, char *s);
+void  pptr(Io *f, void *v);
+void  pstr(Io *f, char *s);
+void  pdec(Io *f, int n);
+void  poct(Io *f, uint n);
+void  pval(Io *f, Word *a);
+void  pcmd(Io *f, Tree *t);
+void  pfmt(Io *f, char *fmt, ...);
+void  vpfmt(Io *f, char *fmt, va_list args); 
+
+/* 
+ * word.c 
+ */
+void pushlist(void);
+void freelist(Word *w);
+void poplist(void);
+
+int   count(Word *w);
+Word *newword(char *w, Word *link);
+void  pushword(char *w);
+
+/* 
+ * tree.c 
+ */
+
+Tree *newtree(void);
+void  freetree(Tree *t);
+Tree *tree3(int type, Tree *c0, Tree *c1, Tree *c2);
+Tree *tree2(int type, Tree *c0, Tree *c1);
+Tree *tree1(int type, Tree *c0);
+
+Tree *hang1(Tree *p, Tree *c0);
+Tree *hang2(Tree *p, Tree *c0, Tree *c1);
+Tree *hang3(Tree *p, Tree *c0, Tree *c1, Tree *c2);
+Tree *epihang(Tree *c, Tree *epi);
+Tree *simplehang(Tree *t);
+Tree *wordnode(char *w);
+
+/*
+ * var.c
+ */
+
+Var  *newvar(char *name, Var *link);
+Var  *gvlookup(char *name);
+Var  *vlookup(char *name);
+
+int  kwlookup(char *name);
+void initkw(void);
+
+/* 
+ * lex.c 
+ */
+
+void skipnl(void);
+int  wordchr(char c);
+
+void rcerror(char *msg, ...);
+int  lex(Tree **node);
+
+/*
+ * parse.c
+ */
+
+int parse(void);
+
+/*
+ * main.c
+ */
+
+void dotrap(void);