Done with some things, saving here.

TODO.md

@@ -1,7 +1,7 @@
-0. Create file to describe properties of terminology used; param, arg, var, &c.
+1. Differentiate parameters and arguments -- params for function definitions,
-1. Differenciate parameters and arguments -- params for function definitions,
 arguments for function calls
-2. Add scope field to all ASTs, and new scope layer for those that need it.
 
 Change editor to GNU Readline.
 Make variables persist through lines in the editor.
+
+Return syntax errors as exceptions.

examples/function.scl

@@ -1,3 +1,3 @@
-f(n) 2 * n
+f(n) = 2 * n
 
 f(5)

src/ast.c

@@ -17,7 +17,9 @@ static char* asttype_names[] = {
     [AST_TYPE_BLOCK] = "BLOCK",
     [AST_TYPE_EXC] = "EXCEPTION",
     [AST_TYPE_FDEF] = "FUNCTION DEFINITION",
-    [AST_TYPE_ARG] = "DEFINITION ARGUMENT"
+    [AST_TYPE_ARG] = "DEFINITION ARGUMENT",
+    [AST_TYPE_LAMBDA] = "LAMBDA EXPRESSION"
+
 };
 
 AST* ast_init(ASTType type, void* data) {
@@ -51,13 +53,14 @@ void ast_destroy(AST* ast) {
     if (!ast) return;
 
     switch (ast->type) {
-        case AST_TYPE_NUM:   ast_num_data_destroy(ast->data); break;
+        case AST_TYPE_NUM:    ast_num_data_destroy(ast->data); break;
-        case AST_TYPE_CALL:  ast_call_data_destroy(ast->data); break;
+        case AST_TYPE_CALL:   ast_call_data_destroy(ast->data); break;
-        case AST_TYPE_VREF:  ast_vref_data_destroy(ast->data); break;
+        case AST_TYPE_VREF:   ast_vref_data_destroy(ast->data); break;
-        case AST_TYPE_VDEF:  ast_vdef_data_destroy(ast->data); break;
+        case AST_TYPE_VDEF:   ast_vdef_data_destroy(ast->data); break;
-        case AST_TYPE_BLOCK: ast_block_data_destroy(ast->data); break;
+        case AST_TYPE_BLOCK:  ast_block_data_destroy(ast->data); break;
-        case AST_TYPE_FDEF:  ast_fdef_data_destroy(ast->data); break;
+        case AST_TYPE_FDEF:   ast_fdef_data_destroy(ast->data); break;
-        case AST_TYPE_ARG:   ast_arg_data_destroy(ast->data); break;
+        case AST_TYPE_ARG:    ast_arg_data_destroy(ast->data); break;
+        case AST_TYPE_LAMBDA: ast_lambda_data_destroy(ast->data); break;
         default:
             log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
@@ -72,15 +75,16 @@ void ast_destroy_psv(AST* ast) {
     if (!ast) return;
 
     switch (ast->type) {
-        case AST_TYPE_NUM:   ast_num_data_destroy(ast->data); break;
+        case AST_TYPE_NUM:    ast_num_data_destroy(ast->data); break;
-        case AST_TYPE_CALL:  ast_call_data_destroy_psv(ast->data); break;
+        case AST_TYPE_CALL:   ast_call_data_destroy_psv(ast->data); break;
-        case AST_TYPE_VREF:  ast_vref_data_destroy(ast->data); break;
+        case AST_TYPE_VREF:   ast_vref_data_destroy(ast->data); break;
-        case AST_TYPE_VDEF:  ast_vdef_data_destroy_psv(ast->data); break;
+        case AST_TYPE_VDEF:   ast_vdef_data_destroy_psv(ast->data); break;
-        case AST_TYPE_BLOCK: ast_block_data_destroy_psv(ast->data); break;
+        case AST_TYPE_BLOCK:  ast_block_data_destroy_psv(ast->data); break;
-        case AST_TYPE_FDEF:  ast_fdef_data_destroy_psv(ast->data); break;
+        case AST_TYPE_FDEF:   ast_fdef_data_destroy_psv(ast->data); break;
-        case AST_TYPE_ARG:   ast_arg_data_destroy(ast->data); break;
+        case AST_TYPE_ARG:    ast_arg_data_destroy(ast->data); break;
-        case AST_TYPE_BIF:   ast_bif_data_destroy(ast->data); break;
+        case AST_TYPE_BIF:    ast_bif_data_destroy(ast->data); break;
-        case AST_TYPE_EXC:   ast_exc_data_destroy(ast->data); break;
+        case AST_TYPE_EXC:    ast_exc_data_destroy(ast->data); break;
+        case AST_TYPE_LAMBDA: ast_lambda_data_destroy(ast->data); break;
         default:
             log_dbgf("Unknown ast type %d (max: %d)", ast->type, AST_TYPE_MAX);
     }
@@ -104,14 +108,15 @@ void ast_print_i(AST* ast, int i) {
         case AST_TYPE_NUM:
             printf("%s  %lf\n", INDENT_spacing->buf, *(ASTNumData*)ast->data);
             break;
-        case AST_TYPE_CALL:  ast_call_print(ast->data, i + 2); break;
+        case AST_TYPE_CALL:   ast_call_print(ast->data, i + 2); break;
-        case AST_TYPE_EXC:   ast_exc_print(ast->data, i + 2); break;
+        case AST_TYPE_EXC:    ast_exc_print(ast->data, i + 2); break;
-        case AST_TYPE_VREF:  ast_vref_print(ast->data, i + 2); break;
+        case AST_TYPE_VREF:   ast_vref_print(ast->data, i + 2); break;
-        case AST_TYPE_VDEF:  ast_vdef_print(ast->data, i + 2); break;
+        case AST_TYPE_VDEF:   ast_vdef_print(ast->data, i + 2); break;
-        case AST_TYPE_BLOCK: ast_block_print(ast->data, i + 2); break;
+        case AST_TYPE_BLOCK:  ast_block_print(ast->data, i + 2); break;
-        case AST_TYPE_FDEF:  ast_fdef_print(ast->data, i + 2); break;
+        case AST_TYPE_FDEF:   ast_fdef_print(ast->data, i + 2); break;
-        case AST_TYPE_ARG:   ast_arg_print(ast->data, i + 2); break;
+        case AST_TYPE_ARG:    ast_arg_print(ast->data, i + 2); break;
-        default:             exit(1);
+        case AST_TYPE_LAMBDA: ast_lambda_print(ast->data, i + 2); break;
+        default:              exit(1);
     }
     INDENT_FIELD_NONL_END;
     INDENT_END;
@@ -344,6 +349,32 @@ void ast_arg_print(ASTArgData* arg, int i) {
     INDENT_END;
 }
 
+ASTLambdaData* ast_lambda_data_init(size_t argc, AST** argv, AST* body) {
+    talloc(ASTLambdaData, lambda);
+
+    lambda->argc = argc;
+    lambda->argv = argv;
+    lambda->body = body;
+
+    return lambda;
+}
+
+void ast_lambda_data_destroy(ASTLambdaData* lambda) {
+    free(lambda->argv);
+    free(lambda);
+}
+
+void ast_lambda_print(ASTLambdaData* lambda, int i) {
+    INDENT_BEGIN(i)
+    INDENT_TITLE("ASTLambdaData", lambda);
+    INDENT_FIELD("argc", "%ld", lambda->argc);
+    INDENT_FIELD_LIST("argv", lambda->argv, lambda->argc, ast_print_i);
+    INDENT_FIELD_EXT_NONL_START("body");
+    ast_print_i(lambda->body, i + 2);
+    INDENT_FIELD_NONL_END;
+    INDENT_END;
+}
+
 AST* ast_find(Scope* scope, char* name) {
     while (scope) {
         AST* gotten = htab_get(scope->here, name);

src/exec.c

@@ -39,10 +39,11 @@ AST* exec_exp(AST* ast, Scope* parent) {
             return ast_init(
                 AST_TYPE_NUM, ast_num_data_init(*(ASTNumData*)ast->data)
             );
-        case AST_TYPE_VREF: return exec_vref(ast, parent);
+        case AST_TYPE_VREF:   return exec_vref(ast, parent);
-        case AST_TYPE_VDEF: return exec_vdef(ast, parent);
+        case AST_TYPE_VDEF:   return exec_vdef(ast, parent);
-        case AST_TYPE_FDEF: return exec_fdef(ast, parent);
+        case AST_TYPE_FDEF:   return exec_fdef(ast, parent);
-        default:            printf("what\n"); exit(1);
+        case AST_TYPE_LAMBDA: return exec_lambda(ast, parent);
+        default:              printf("what\n"); exit(1);
     }
 }
 
@@ -79,7 +80,8 @@ AST* exec_call(AST* ast, Scope* parent) {
         case AST_TYPE_BIF:
             ASTBIFData bifdata = fdef->data;
             return bifdata(argc, argv, parent);
-        case AST_TYPE_FDEF: return exec_cf(fdef, argc, argv);
+        case AST_TYPE_FDEF:   return exec_cf(fdef, argc, argv);
+        case AST_TYPE_LAMBDA: return exec_lambda_call(fdef, argc, argv);
         default:
             return ast_init(AST_TYPE_EXC, ast_exc_data_init("Good job!", NULL));
     }
@@ -132,14 +134,29 @@ AST* exec_vref(AST* ast, Scope* parent) {
 AST* exec_fdef(AST* ast, Scope* parent) {
     ast->scope = scope_init(parent);
     ASTFDefData* fdef = (ASTFDefData*)ast->data;
-    log_dbgf("IS THIS SUSPICIOUS??? %i", fdef->body->type);
     AST* val = ast;
     char* key = fdef->name;
     scope_add(parent, key, val);
-    // TODO: Create lambda functions.
     return fdef->body; // Function definitions return function body.
 }
 
+AST* exec_lambda(AST* ast, Scope* parent) {
+    // Executing a lambda on its own with no arguments returns itself.
+    return ast;
+}
+
+AST* exec_lambda_call(AST* ast, size_t argc, AST** argv) {
+    Scope* callscope = scope_init(ast->scope);
+    ASTFDefData* lambda = (ASTFDefData*)ast->data;
+    for (int i = 0; i < argc; i++) {
+        char* key = ((ASTArgData*)lambda->argv[i]->data)->name;
+        AST* val = argv[i];
+        scope_add(callscope, key, val);
+    }
+
+    return exec_exp(lambda->body, callscope);
+}
+
 void exec_print(double n) { printf("= %lf\n", n); }
 
 inline void exec_new_scope(AST* ast, Scope* inherit) {

src/grammar.y

@@ -47,6 +47,8 @@
 
 %token NL // Newline.
 
+%token BACKSLASH
+
 %left ADD SUB
 %left MUL DIV
 %precedence NEG
@@ -125,13 +127,31 @@ exp:
     NUM { $$ = ast_init(AST_TYPE_NUM, ast_num_data_init($1)); }
 
     // Function definitions.
-    | WORD GROUPS arg GROUPE EQ exp {
+    | WORD GROUPS arg GROUPE exp {
         size_t argc = $3->ln;
         AST** argv = $3->buf;
         argarr_destroypsv($3);
-        $$ = ast_init(AST_TYPE_FDEF, ast_fdef_data_init($1, argc, argv, $6));
+        $$ = ast_init(AST_TYPE_FDEF, ast_fdef_data_init($1, argc, argv, $5));
     }
 
+    // Lambda definitions.
+    | BACKSLASH GROUPS arg GROUPE exp {
+        size_t argc = $3->ln;
+        AST** argv = $3->buf;
+        argarr_destroypsv($3);
+        $$ = ast_init(AST_TYPE_LAMBDA, ast_lambda_data_init(argc, argv, $5));
+    }
+
+    /*
+    // Inline call.
+    | exp GROUPS arg GROUPE {
+        size_t argc = $3->ln;
+        AST** argv = $3->buf;
+        argarr_destroypsv($3);
+        $$ = ast_init(AST_TYPE_CALL, ($1, argc, argv));
+    }
+    */
+
     | BLOCKS block BLOCKE {
         $$ = ast_init(AST_TYPE_BLOCK, ast_block_data_init((AST**) $2->buf, $2->ln));
     }

src/include/ast.h

@@ -18,13 +18,14 @@ typedef enum {
     AST_TYPE_LIST, // A list (variable size, variable type).
 
     // Misc. types.
-    AST_TYPE_BIF,   // Built-in function.
+    AST_TYPE_BIF,    // Built-in function.
-    AST_TYPE_CALL,  // A function call.
+    AST_TYPE_CALL,   // A function call.
-    AST_TYPE_VDEF,  // A variable definition.
+    AST_TYPE_VDEF,   // A variable definition.
-    AST_TYPE_VREF,  // A variable reference.
+    AST_TYPE_VREF,   // A variable reference.
-    AST_TYPE_BLOCK, // A block of code (scope).
+    AST_TYPE_BLOCK,  // A block of code (scope).
-    AST_TYPE_FDEF,  // A function definition.
+    AST_TYPE_FDEF,   // A function definition.
-    AST_TYPE_ARG,   // A definition argument.
+    AST_TYPE_LAMBDA, // An anonymous function definition.
+    AST_TYPE_ARG,    // A definition argument.
     AST_TYPE_MAX = AST_TYPE_ARG,
 } ASTType;
 
@@ -60,8 +61,8 @@ void ast_num_print(ASTNumData*, int i);
 
 // An exception.
 typedef struct ASTEXCDATA {
-    const char* msg;  // The exception message.
+    const char* msg; // The exception message.
-    AST* trace; // The previous exception.
+    AST* trace;      // The previous exception.
 } ASTExcData;
 // Create a new `ASTExecData. `msg` should be static.
 ASTExcData* ast_exc_data_init(const char* msg, AST* trace);
@@ -70,6 +71,13 @@ void ast_exc_data_destroy(ASTExcData* exc);
 // Print an `ASTExecData`.
 void ast_exc_print(ASTExcData*, int i);
 
+// arguments list as anonymous struct
+#define ARGS                                                                   \
+    struct {                                                                   \
+        size_t argc;                                                           \
+        AST** argv;                                                            \
+    }
+
 // A built-in function.
 typedef AST* (*ASTBIFData)(size_t argc, AST** argv, Scope* scope);
 
@@ -80,9 +88,8 @@ void ast_bif_data_destroy(ASTBIFData* bif);
 
 // A call (to a function).
 typedef struct {
-    char* to;    // What the call's to.
+    char* to; // What the call's to.
-    size_t argc; // Argument count.
+    ARGS;     // argument list
-    AST** argv;  // Argument vector.
 } ASTCallData;
 
 // Create a new `ASTCallData`.
@@ -90,7 +97,7 @@ ASTCallData* ast_call_data_init(char* to, size_t argc, AST** argv);
 // Destroy an `ASTCallData` recursively.
 void ast_call_data_destroy(ASTCallData* call);
 // Destroy an `ASTCallData`.
-void ast_call_data_destroy_psv(ASTCallData *call);
+void ast_call_data_destroy_psv(ASTCallData* call);
 // Print an `ASTCallData`.
 void ast_call_print(ASTCallData*, int i);
 
@@ -132,15 +139,14 @@ ASTBlockData* ast_block_data_init(AST** inside, size_t ln);
 // Destroy an `ASTBlockData`, recursively.
 void ast_block_data_destroy(ASTBlockData* block);
 // Destroy an `ASTBlockData`.
-void ast_block_data_destroy_psv(ASTBlockData *block);
+void ast_block_data_destroy_psv(ASTBlockData* block);
 // Print an `ASTBlockData`.
 void ast_block_print(ASTBlockData*, int i);
 
 typedef struct {
-    char* name;  // Function name.
+    char* name; // Function name.
-    size_t argc; // Argument count.
+    ARGS;       // Function args.
-    AST** argv;  // Argument vector.
+    AST* body;  // Function body.
-    AST* body;   // Function body.
 } ASTFDefData;
 
 // Create a new `ASTFDefData`.
@@ -163,6 +169,19 @@ void ast_arg_data_destroy(ASTArgData* arg);
 // Print an `ASTArgData`.
 void ast_arg_print(ASTArgData* arg, int i);
 
+// Represents a function as data.
+typedef struct {
+    ARGS;
+    AST* body;
+} ASTLambdaData;
+
+// Creates a new `ASTLambdaData`.
+ASTLambdaData* ast_lambda_data_init(size_t argc, AST** argv, AST* body);
+// Destroy an `ASTLambdaData`.
+void ast_lambda_data_destroy(ASTLambdaData*);
+// Print an `ASTLambdaData`.
+void ast_lambda_print(ASTLambdaData* arg, int i);
+
 // Find a name in the scope.
 AST* ast_find(Scope* scope, char* name);
 

src/include/exec.h

@@ -20,6 +20,10 @@ AST* exec_vdef(AST* ast, Scope* parent);
 AST* exec_vref(AST* ast, Scope* parent);
 // Execute a function definition.
 AST* exec_fdef(AST* ast, Scope* parent);
+// Execute a lambda expression.
+AST* exec_lambda(AST* ast, Scope* parent);
+// Execute a lambda call.
+AST* exec_lambda_call(AST* ast, size_t argc, AST** argv);
 // Print the result of an execution.
 void exec_print(double n);
 

src/include/util.h

@@ -1,6 +1,8 @@
 #ifndef UTIL_H
 #define UTIL_H
 
+#include <signal.h>
+
 // Most of this file is cursed printing macros for `ast_print()`. Do not attempt
 // to comprehend.
 
@@ -10,6 +12,9 @@
 // Get the length of an array.
 #define arrln(A) (sizeof(A)/sizeof(*A))
 
+// Trap GDB &c.
+#define TRAP() RAISE(SIGTRAP)
+
 #ifdef DBG // Debug macros
 
 // Log a message.

src/lexer.c

@@ -116,6 +116,7 @@ int yylex() {
         case '{':  return BLOCKS;
         case '}':  return BLOCKE;
         case '=':  return EQ;
+        case '\\': return BACKSLASH;
         default:   fprintf(stderr, "Unexpected character: %c\n", c);
     }